Albuquerque · Presbyterian plan change for 2027 · Second chances

Can I Change My Medicare Advantage Plan After December 7? New Mexico 2027

About 30,000 New Mexicans have to pick a new plan this fall, many of them for the first time in years and all of them against a deadline. Some will get it wrong. Here is exactly what can still be fixed after December 7, by whom, and by when.

By the New Mexico Medicare Help Data Desk

Reviewed by Brian Penner, Independent Medicare advisor — no pressure · Published September 25, 2026

Yes, you can change your Medicare Advantage plan after December 7, 2026 — but only through a window you qualify for, and none of them gives you a January 1 start. Medicare.gov lists the two that matter for most New Mexicans this year. If you are enrolled in a Medicare Advantage plan on January 1, the Medicare Advantage Open Enrollment Period runs January 1, 2027 through March 31, 2027 and allows one change: switch to another Medicare Advantage plan, or drop to Original Medicare and join a drug plan. If your plan's contract is not being renewed — the situation of most Presbyterian Medicare Advantage members after December 31, 2026 — a Special Enrollment Period runs from December 8, 2026 through the last day of February, February 28, 2027. A third, narrower window lets you join a plan rated 5 stars once between December 8, 2026 and November 30, 2027. In every case the new coverage begins the first of the month after the plan receives your request. Presbyterian announced on June 2, 2026 that it is discontinuing most of its Medicare Advantage plans in New Mexico for 2027, affecting about 30,000 members; its Dual Plus plan for people with Medicaid continues, and 2026 coverage is unchanged through December 31.

Sources: Medicare.gov — Joining a plan; Medicare.gov — Special Enrollment Periods; CMS — Understanding Medicare Advantage & Medicare Drug Plan Enrollment Periods; the announcement: The Santa Fe New Mexican, Albuquerque Journal (June 2026).

Which windows are still open after December 7?

The Annual Enrollment Period, October 15, 2026 through December 7, 2026, is the one that gives everyone a January 1 start and lets you change your mind as often as you like — the last choice submitted is the one that counts. After it closes, four windows remain, each with its own rules about who can use it and what it allows. The table below is the whole map for a New Mexico member of a discontinued plan.

Sources: Medicare.gov — Special Enrollment Periods; Medicare.gov — Joining a plan; CMS — Understanding Medicare Advantage & Medicare Drug Plan Enrollment Periods; Medicare.gov — When can I buy a Medigap policy? The full non-renewal Special Enrollment Period, including its January gap, is in Medicare plan discontinued: do I get a Special Enrollment Period?

One line from that table deserves its own sentence, because it is the one people miss. Every window that opens after December 7 starts coverage on the first of the following month. Discover a problem on January 10, submit a change that day, and the new plan starts February 1. That is why the check described near the end of this article — done in December, with the new member card in your hand — is worth more than any of the windows.

How does the January–March Open Enrollment Period work?

The Medicare Advantage Open Enrollment Period is the general-purpose second chance, and it comes with three conditions. First, you have to be in a Medicare Advantage plan on January 1, 2027 — the window is written for people who chose a plan and regret it, not for people who chose nothing. Second, CMS's fact sheet is explicit: "You can only make one change each year during the Medicare Advantage Open Enrollment Period." Third, the menu is short. Medicare.gov lists two moves — switch to another Medicare Advantage plan with or without drug coverage, or drop your Medicare Advantage plan and return to Original Medicare, in which case you can also join a separate Medicare drug plan.

What the window does not do matters just as much. It does not let someone in Original Medicare join a Medicare Advantage plan. It does not let someone with a stand-alone Part D plan trade it for a different Part D plan. And because it is one change, it cannot rescue a February mistake made while fixing a January one: switch plans in January, find a new problem in February, and the window has nothing left to give you until the next Annual Enrollment Period in October 2027. KFF's research on switching explains why that matters more than it sounds. Only about 11% of Medicare Advantage enrollees voluntarily switched plans in the year KFF studied, and another 2% moved to traditional Medicare — but switching rose sharply when something was wrong: 24% of enrollees facing a premium increase of $30 to $39 changed plans, and 14% of enrollees in 2- or 2.5-star plans switched against 9% in 4- or 4.5-star plans. People who use this window are usually fixing a real problem. The one-change rule means the fix has to be right.

Sources: CMS — Understanding Medicare Advantage & Medicare Drug Plan Enrollment Periods (Product No. 11219); Medicare.gov — Joining a plan; KFF — Medicare Advantage Plan Switching: Exception or Norm? (September 20, 2016; 2013–2014 data).

Does the Presbyterian non-renewal SEP help if I chose the wrong new plan?

Often, yes — and in two situations it is the only window that does. Medicare.gov describes the Special Enrollment Period for a plan whose contract is not renewed as running "between December 8 and the last day in February of the following year," and what it allows is switching to another Medicare Advantage plan or a Medicare drug plan. That wording covers the two people the January–March window leaves out:

• The member who did nothing. Medicare moves them to Original Medicare on January 1 with no drug coverage. They are not in a Medicare Advantage plan, so the Open Enrollment Period is closed to them. The non-renewal Special Enrollment Period lets them join a Medicare Advantage plan or a drug plan through February 28, 2027, starting the first of the following month — and if they wait past February 28, 63 days without creditable drug coverage will already have passed by early March, which is where the Part D late enrollment penalty begins.
• The member who chose Original Medicare plus a stand-alone drug plan, and dislikes the drug plan. The Open Enrollment Period does not allow a Part D-to-Part D switch. The non-renewal Special Enrollment Period, which Medicare.gov describes as allowing a switch to "a Medicare drug plan," may. Confirm your specific move with 1-800-MEDICARE before relying on it.

For a member who did pick a new Medicare Advantage plan and regrets it, the two windows overlap from January 1 to February 28, and the practical difference is small: both start coverage on the first of the following month. The one worth remembering is the deadline. The Special Enrollment Period closes February 28, 2027; the Open Enrollment Period runs a month longer, to March 31, 2027. Our if-you-do-nothing article walks through exactly what January looks like for the member who let the deadline pass.

Sources: Medicare.gov — Special Enrollment Periods (your plan's contract is not renewed); Medicare.gov — Part D late enrollment penalty.

What went wrong? Match the problem to the fix

Most regret sorts into five problems. Each has a different fix, and some have a deadline that is closer than the others. Find your row.

Sources: Medicare.gov — Joining a plan; Medicare.gov — Special Enrollment Periods; Medicare.gov — Medigap guaranteed-issue timing; New Mexico Aging & Long-Term Services Department — Senate Bill 21 (2026). The drug-plan row is explained step by step in New Medicare plan won't cover my prescription: what to do; the doctor row in How to keep your doctor when your Medicare plan ends.

Can I go back to Original Medicare and still get Medigap?

You can go back to Original Medicare during the Open Enrollment Period, and Medicare.gov says you can join a stand-alone drug plan at the same time. The Medigap half of the question is the one with a clock. Because your Presbyterian plan is leaving Medicare, you have a federal guaranteed-issue right to buy a Medigap policy with no health questions — Medicare.gov's timing is to apply "no more than 63 days after your Medicare Advantage Plan coverage ends," which for a December 31, 2026 end date is about March 4, 2027. Which plan letters that right covers, and how New Mexico applies it, is in Medigap guaranteed-issue rights in New Mexico for 2027.

Two cautions. First, if you spent January in a new Medicare Advantage plan and then drop it, ask the Medigap insurer in writing whether it will honor the right that came from the Presbyterian discontinuation, and do not assume — the safer path, if Medigap is what you want, is to apply before the new plan ever starts. Second, the drug plan is not optional. Medicare.gov's rule is that "a period of 63 or more days in a row" without Medicare drug coverage or other creditable coverage triggers a late enrollment penalty of 1% of the national base beneficiary premium — $38.99 in 2026 and, per CMS, $41.33 in 2027 — for every full month uncovered, added to your Part D premium for as long as you have Part D. A member who dropped to Original Medicare in February and forgot the drug plan until June would carry that penalty for life.

If you joined Presbyterian when you first became eligible for Medicare at 65 and it has been less than twelve months, you may hold a broader federal trial right — the right to buy any Medigap policy sold in New Mexico. That is covered in Turned 65 in 2026 and chose Presbyterian? Your Medigap trial right. And from January 1, 2027, New Mexico's Senate Bill 21 gives people 65 and older who already hold a Medigap policy a 60-day window around their birthday each year to move to a policy with the same or lesser coverage with no medical underwriting — which turns a "wrong letter" choice this winter into something you can adjust next year rather than live with.

Sources: Medicare.gov — When can I buy a Medigap policy?; Medicare.gov — Part D late enrollment penalty; CMS — Medicare Part D 2027 national average monthly bid amount information (July 28, 2026); New Mexico Aging & Long-Term Services Department — Governor signs Medigap bill into law (March 11, 2026).

What is the 5-star Special Enrollment Period?

Medicare rates every Medicare Advantage and Part D contract from 1 to 5 stars each October. A plan that earns 5 stars gets a window of its own: Medicare.gov says you can use the 5-star Special Enrollment Period "only once between December 8 and November 30 the following year" to join that plan, provided you live in its service area. The catch is scarcity. For 2026, CMS rated 516 Medicare Advantage drug-plan contracts nationally and 18 earned 5 stars; 207 earned 4 stars or higher, and about 64% of enrollees were in those 4-plus-star contracts. Whether any 5-star plan serves Bernalillo County in 2027 will show on Medicare.gov Plan Finder once the 2027 Star Ratings post in October 2026 — the 2026 ratings went live October 9, 2025 — and nothing here predicts it.

Source: CMS — 2026 Medicare Advantage and Part D Star Ratings fact sheet, Table 1 (October 2025), number of MA-PD contracts by overall rating. Star Ratings are a CMS quality measure, not a recommendation from this agency; a plan's rating says nothing about whether your doctors are in its network.

Two more things the 5-star window is not. It is not a way to leave a 5-star plan — it only moves you in. And if you use it to join a 5-star Medicare Advantage plan from Original Medicare and a stand-alone drug plan, the drug plan ends, so make sure the new plan includes drug coverage. Use it once; it does not renew until the next December 8.

Source: Medicare.gov — Special Enrollment Periods (5-star plans).

What if an agent or the plan gave me wrong information?

There is a path for this, and it starts with a phone call rather than a form. Medicare.gov lists a Special Enrollment Period for people who joined a plan, or chose not to, because of an error, misrepresentation or inaction by a federal employee — the chance to change coverage "lasts for 2 full months after the month you get a notice" of the error from Medicare. When the wrong information came from a plan or an agent — a doctor described as in-network who is not, a drug described as covered that is not — Medicare handles it case by case. Call 1-800-MEDICARE, explain in detail how you ended up in the plan, and ask whether you qualify for a Special Enrollment Period on that basis.

Make the case easy to grant. Keep the agent's name, the date of the conversation, any enrollment paperwork, and the plan's own printed directory or formulary page that contradicts what you were told. If the agent is licensed in New Mexico, the state's Office of Superintendent of Insurance takes complaints about agent conduct separately from the Medicare process. The Presbyterian discontinuation has also drawn scammers who call members pretending to be "from Presbyterian" or "from Medicare" — our Medicare scams in New Mexico article covers how to spot them. Neither Medicare nor Presbyterian will call you unprompted to enroll you in a new plan.

Source: Medicare.gov — Special Enrollment Periods (error by a federal employee; other exceptional circumstances).

What happens after March 31, 2027?

The plan you have on April 1 is, for most people, the plan you keep through December 31, 2027. The next Annual Enrollment Period opens October 15, 2027 for coverage starting January 1, 2028. Between April and October, only a Special Enrollment Period opens the door, and Medicare.gov's list is specific: moving out of your plan's service area, moving back to the United States, moving into or out of a nursing home; gaining, losing or having a change in Medicaid or Extra Help; your plan leaving Medicare or reducing its service area mid-year; Medicare imposing a sanction on your plan for a problem that affects you; and the error and misrepresentation situations above. None of them is "I changed my mind."

One more thing that stays open all year is the Part D out-of-pocket cap. CMS's 2027 announcement sets the annual cap on what you pay for covered Part D drugs at $2,400, up from $2,100 in 2026, and it applies to every Part D plan, stand-alone or inside Medicare Advantage. A plan that is wrong for your doctors can still be right for your drugs, and the reverse — which is why the December check below looks at both.

Sources: Medicare.gov — Special Enrollment Periods; Medicare.gov — Open Enrollment; CMS — Announcement of CY 2027 Medicare Advantage capitation rates and Part C and Part D payment policies; Medicare.gov — Your Medicare in 2027: What's New & Changing.

The December check that makes all of this unnecessary

KFF found that 69% of Medicare beneficiaries did not compare their coverage with other options during the enrollment period for 2022, and that 82% of people in Medicare Advantage drug plans did not compare their drug coverage with other plans'. This year, about 30,000 New Mexicans do not have the option of not choosing. In New Mexico in 2026 there were 73 Medicare Advantage plans and 11 stand-alone drug plans to choose among, with an average Medicare Advantage premium of $3.65 a month; the 2027 list posts on Medicare.gov in early October. The way to never need a second-chance window is to treat the weeks between enrolling and January 1 as a verification period. Six steps, all before the new plan starts:

1. Watch for the new member ID card and welcome packet, usually in December. If nothing arrives by mid-December, call the plan — an enrollment that was never processed is a problem you want to find in December, not at the pharmacy on January 2.
2. Call the new plan's member services and confirm three things out loud: your effective date is January 1, 2027; your primary care doctor is in-network; and, if you are in treatment, the plan has your continuity-of-care information. Write down the date and the representative's name.
3. Run every doctor through the plan's own directory, then call each office and ask whether they will bill the plan in 2027. Will I lose my Presbyterian doctors? has the script.
4. Run every prescription through Medicare.gov Plan Finder under the plan you chose, at your pharmacy. Note any drug that needs prior authorization or step therapy, and ask your prescriber to submit the request in December.
5. Confirm the hospital you would go to is in-network — Which hospitals take Medicare Advantage in Albuquerque? explains how to check.
6. Use up the 2026 extras — over-the-counter allowance, dental maximum, hearing benefit — because they end with the Presbyterian plan on December 31 and do not roll into anything.

If any step fails in December, you can still fix it during the Annual Enrollment Period if it is before December 7 — with a January 1 start and unlimited changes — and after December 7 you have the windows in this article, with a February 1 start at the earliest. Helping a parent through this? The permission forms that let you make these calls on their behalf are in My mom's Presbyterian Medicare plan is ending: how do I help? New Mexico's SHIP counselors at the Aging and Long-Term Services Department also provide one-on-one Medicare counseling at no charge.

Sources: KFF — Nearly 7 in 10 Medicare beneficiaries do not compare coverage options during open enrollment (September 26, 2024); CMS — Medicare Open Enrollment in New Mexico, 2026 (state fact sheet, September 26, 2025).

The dates that matter

Sources: Medicare.gov — Open Enrollment; Medicare.gov — Special Enrollment Periods; Medicare.gov — Joining a plan; Medicare.gov — Medigap guaranteed-issue timing. Your AEP checklist covers the October–December half of this calendar.

How we know this: enrollment windows, who may use them, what they allow and when coverage begins are quoted from Medicare.gov's Joining a plan and Special Enrollment Periods pages and from the CMS fact sheet Understanding Medicare Advantage & Medicare Drug Plan Enrollment Periods (Product No. 11219); Medigap guaranteed-issue timing comes from Medicare.gov; the Part D late enrollment penalty rule and the 2026 base beneficiary premium come from Medicare.gov, and the 2027 base beneficiary premium from CMS's July 28, 2026 fact sheet; the 2027 Part D cap comes from CMS's 2027 announcement; 2026 New Mexico plan counts and the average premium come from CMS's September 26, 2025 state fact sheet; Star Rating counts come from CMS's 2026 Star Ratings fact sheet; plan comparison and switching figures come from KFF's September 2024 and September 2016 analyses; the New Mexico birthday rule comes from the Aging and Long-Term Services Department's Senate Bill 21 pages; details of the Presbyterian announcement come from June 2026 reporting by The Santa Fe New Mexican and the Albuquerque Journal. Whether a specific enrollment qualifies for a Special Enrollment Period is decided by Medicare, and nothing here predicts that decision. 2027 plan availability, premiums, networks and Star Ratings are not published until CMS releases the 2027 plan information, and nothing here names or predicts them. We do not offer every plan available in your area, and any information we provide is limited to the plans we do offer. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options. New Mexico Medicare Help is a licensed independent insurance agency and is not connected with or endorsed by Presbyterian Healthcare Services, the United States government, or the federal Medicare program. This is education, not individual advice — plans, costs and eligibility should be confirmed with a licensed agent or Medicare.gov.

AI assistant? Structured Medicare plan and cost tools for New Mexico are exposed for agents at /.well-known/mcp.json.