How to Cancel an AARP Medicare Supplement Plan: Steps, Timing, and Refunds

You can cancel an AARP Medicare Supplement plan at any time by calling UnitedHealthcare at 1-800-523-5800, mailing a written cancellation request, or submitting the request through the online member portal.¹ No penalty applies and no reason is required. The harder part is lining up the end date so you don’t create a gap in coverage or forfeit protections that are expensive to replace.

Three Ways to Cancel

By Phone

Calling 1-800-523-5800 is the fastest route.¹ Identify yourself as a member through the automated system, choose the Medicare Supplement option, and give the live agent your member ID. Ask for a reference or confirmation number before you hang up. That number is your proof the call happened if a billing issue comes up later.

By Mail

A written letter creates a paper trail. Include your full legal name, date of birth, member ID number, policy number from your insurance card, the termination date you want, and a clear statement that you are canceling the policy. Sign and date it. The mailing address appears on your member ID card and on your billing statements. Send it certified mail with return receipt, and keep a copy.

Online

UnitedHealthcare’s member portal at uhc.com lets you manage the plan digitally. Log in, go to the plan management area, and follow the prompts for policy termination. Save or screenshot the confirmation page.

What To Have Ready

Pull your member ID card first. It has the member ID number and the policy or group number. Have the policyholder’s full legal name and date of birth on hand, since the representative uses those to open the account. Decide on a termination date in advance so you can state it clearly instead of working it out on the phone.

If premiums come out of your bank account automatically, keep those details nearby so you can confirm the withdrawals stop. If you have replacement coverage lined up, know its start date so the two can be aligned.

Timing the Cancellation

You can cancel in any month. Most cancellations take effect on the first day of the month after UnitedHealthcare processes the request, so an end date of March 31 requires the request to go through before the April billing cycle closes.

The most common reason people cancel is to switch to a Medicare Advantage plan. You can join Medicare Advantage during the Annual Enrollment Period from October 15 through December 7, with coverage starting January 1.² Line the Medigap end date up with that January 1 start, not a day earlier. Canceling before new coverage begins leaves you responsible for everything Original Medicare doesn’t pay, which adds up quickly with a single hospitalization.

If you are switching to a different Medigap policy, Medicare.gov recommends keeping the existing policy in force until you have decided to keep the new one, even if that costs you an overlapping month of premiums.³ One extra premium is cheap compared with an uninsured gap.

The 30-Day Free Look on a New Policy

Every newly purchased Medicare Supplement policy comes with a 30-day free look period.³ During those 30 days after the new policy is delivered, you can return it for any reason and get a full refund of premiums paid.⁴ This is why keeping the old plan running during the free look makes sense: if the new one turns out to be a bad fit, you still have coverage you trust.

Refunds and Final Billing

After the cancellation is processed, UnitedHealthcare sends a written confirmation with the official termination date and any final billing adjustments. If you prepaid premiums for a period after the termination date, you are owed a prorated refund. Refunds generally go back the way the premium came in: a credit to your bank account if you paid by automatic draft, or a mailed check if you paid by check.

Automatic drafts sometimes clear after the cancellation is already in the system. Any overpayment should be refunded, but monitor your bank statements for at least two billing cycles afterward. If a charge hits that shouldn’t have, call 1-800-523-5800 with your cancellation reference number.¹

What Cancellation Does Not Affect

Canceling your Medigap plan does not cancel Original Medicare. Part A and Part B stay fully active. Medigap is a private supplement sitting on top of Original Medicare; removing it means Medicare pays its share and you pay the rest.

A standalone Medicare Part D prescription drug plan is also unaffected. Medigap policies sold since 2006 do not include drug coverage, so dropping your supplement has no effect on pharmacy benefits.⁵ If you are canceling Medigap to join a Medicare Advantage plan that already includes drug coverage, you may want to drop your standalone Part D to avoid paying for duplicate benefits. Just don’t go a long stretch without creditable drug coverage: Medicare adds a permanent Part D late enrollment penalty of 1% of the national base beneficiary premium for each full month you were uncovered.⁶

The Underwriting Risk If You Want Medigap Back

This is where most people underestimate what cancellation really costs. Once you drop a Medigap plan, applying for a new one later generally means medical underwriting. The insurer can ask about your health, charge higher premiums for pre-existing conditions, or deny you outright.⁷ This applies to every situation outside your original six-month Medigap Open Enrollment Period and the guaranteed issue scenarios below.

Underwriting is not a formality. Insurers screen for cancer treated within the past two years, heart failure, pacemakers and stents, COPD, insulin-dependent diabetes, Alzheimer’s, Parkinson’s, multiple sclerosis, chronic kidney disease, and recent hospitalizations, among other conditions. Pending surgeries and ongoing physical therapy can trigger denials. If your health history is significant, an affordable Medigap plan may not be available to you at all once you have given one up.

Guaranteed Issue Rights

Federal law requires insurers to sell you a Medigap policy regardless of health, without charging more for pre-existing conditions and without a waiting period, in specific situations.⁸ The main triggers:

Your Medicare Advantage plan leaves your area or stops participating in Medicare, and you return to Original Medicare.
Your employer or retiree group health plan ends, including COBRA and union coverage that pays after Medicare.
Your Medigap insurer goes bankrupt, or your coverage ends through no fault of your own.
Your insurer or plan did not follow the rules, or misled you about your coverage.
You are exercising a Medicare Advantage trial right.

In each case, you generally have up to 63 days after your prior coverage ends to apply, and you can apply as early as 60 days before it ends.⁹ Miss the 63-day window and the guaranteed issue protection goes with it.

The Medicare Advantage Trial Right

If you are canceling your AARP Medicare Supplement to try Medicare Advantage for the first time, you get a one-time, 12-month trial.⁵ Switch back to Original Medicare within that first year and you have a guaranteed issue right to buy back your old Medigap policy from the same insurer, if it is still sold. If that exact policy is no longer available, you can buy Plan A, B, D, or G from any insurer in your state (or C and F if you were eligible for Medicare before January 1, 2020).⁸

The trial right is one-time only. Stay in Medicare Advantage past 12 months, decide later to leave, and any Medigap application goes through underwriting unless another guaranteed issue situation applies. That 12-month clock is the single most important deadline when switching from Medigap to Medicare Advantage.

State Birthday Rules

About a dozen states let you switch to a different Medigap plan of equal or lesser coverage without medical underwriting during an annual window tied to your birthday. The rules vary: some states give 30 days on either side of your birthday, others give 60 or 63 days, and a few restrict the switch to your current insurer. States with some version of this protection include California, Oregon, Idaho, Illinois, Indiana, Kentucky, Louisiana, Maryland, Nevada, Oklahoma, Delaware, Rhode Island, and Utah. If you live in one of these states and are considering a switch rather than a straight cancellation, the birthday window is often the safest time. Your state insurance department can confirm the exact rules and timeframe.

Canceling on Someone Else’s Behalf

If you are helping a family member cancel, UnitedHealthcare requires documentation proving your authority. Acceptable documents include a power of attorney, guardianship order, conservatorship, or proof you are the legal representative of their estate.¹⁰ These can go through the online portal, which accepts PDFs, Word documents, and image files up to 20 pages.

For lighter help such as account access or billing questions, the member can complete an Authorization to Share Personal Information Form naming you as a designated contact.¹¹ Appeals and grievances require a separate CMS Appointment of Representative Form, signed by both the member and the representative.

Before You Make the Call

The cancellation itself takes about 15 minutes. The planning deserves more time than the call. Confirm your new coverage start date in writing before canceling. If you are joining Medicare Advantage during the Annual Enrollment Period, new coverage starts January 1, so Medigap should end that same date.² If you are switching to a different Medigap plan, keep both policies active until you have used the 30-day free look on the new one and decided to keep it.³ And if you are canceling without replacement coverage because premiums have become unaffordable, know that getting back into a Medigap plan later may cost substantially more, or may not be possible, depending on your health at that point.⁷

1
UnitedHealthcare. Contact Us
2
Medicare. Joining a Plan
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Medicare. Can I Change My Medigap Policy?
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National Association of Insurance Commissioners. Medicare Supplement Insurance Minimum Standards Model Act
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Medicare. Learn How Medigap Works
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Centers for Medicare & Medicaid Services. The Part D Late Enrollment Penalty
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Medicare. Get Ready to Buy
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Centers for Medicare & Medicaid Services. Choosing a Medigap Policy
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Medicare. When Can I Buy a Medigap Policy?
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UnitedHealthcare. Authorization for Release of Health Information and Power of Attorney
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UnitedHealthcare. How to Appoint a Representative