Seniors face an end-of-day deadline Thursday if they want to switch health plans during the Medicare Advantage open-enrollment period.

Advocates say the switching period can be helpful for seniors who want to make a one-time change because they've found problems with their Medicare Advantage coverage, where seniors opt to receive government benefits through a private health insurer.

This open-enrollment period, which was reinstated by the federal government a few years ago, typically gets much less attention than the annual Medicare sign-up period from October through early December.

"This second Medicare Advantage open-enrollment period is January 1 through March 31," said Robin Thompson, information and assistance director with the Minnesota River Area Agency on Aging. "They have one election, so they would be eligible to enroll in a different Medicare Advantage plan."

In recent weeks, some seniors in certain Medicare Advantage plans have been frustrated to find they either can't schedule appointments at the Mayo Clinic or must pay more to visit a new medical facility in Albert Lea.

When considering changes to address such issues, seniors want to be careful, advocates say, that they don't inadvertently walk into new problems by opting for new coverage.

During the Medicare Advantage open-enrollment period that ends Thursday, seniors can opt for a return to the original Medicare program. This change, however, doesn't guarantee that a senior will be able to buy a Medicare Supplement policy, since carriers generally can screen out seniors with health problems.

Often called "Medigap" policies, supplemental coverage significantly reduces out-of-pocket costs for people in original Medicare.

Medicare Advantage plans are increasingly popular in Minnesota and across the country, but the coverage typically includes network rules that limit choices of doctors and hospitals.

In February, the Star Tribune reported that Mayo Clinic had stopped scheduling appointments for seniors in certain Medicare Advantage health plans because their insurers hadn't negotiated contracts for in-network access to the world-renowned medical center. The clinic said it stopped making appointments for these patients this winter to address capacity concerns.

In March, the Star Tribune reported that seniors living in the southern Minnesota town of Albert Lea had complained to Attorney General Keith Ellison that their Medicare Advantage coverage with Blue Cross and Blue Shield of Minnesota didn't provide in-network access to a new clinic that advocates in town had worked years to recruit.

Seniors can review their coverage options at the state's Senior LinkAge Line (800-333-2433) or by working with an insurance agent. They also can use the Medicare Plan Finder website or call Medicare for help (800-633-4227).

Thompson said the Senior LinkAge Line will be open until 4:30 p.m. on Thursday. The Medicare website is available for sign-ups at all hours. Thompson recommends seniors who enroll in coverage through the website print their electronic confirmation.

Most years, there's not a lot of activity during the open-enrollment period, Thompson said, in part because it's not well known.

"It's still very early in the year, so a person may not have used health care or have needed to go to a specialist where [the network] could be an issue," she said, adding that seniors sometimes will find the nearby nursing home they'd like to use is out-of-network.

Even after Thursday's deadline, there still are limited options for making changes with Medicare Advantage coverage, Thompson said, so seniors who find problems should check to see if they qualify for a special enrollment period.