The limited-time Medicare Part D open enrollment period is going on now and while seniors need to think about enrolling in the program or updating their current plans, a federal entity is reminding not to forget about another enrollment period going on.

Medicare Part B has a much longer enrollment period that begins when coverage of a group healthcare plan runs out. Jack Myers with Social Security indicates if you are already enrolled in Medicare Part A, but chose not to enroll in Part B because you or a family member was still working and you were covered by a group health plan based on that work, you may qualify for a special enrollment period when the work or group coverage ends. The enrollment period is an 8-month window that starts when employment or GHP coverage ends.

To enroll in Medicare Part B during an enrollment period you will need to submit a couple of forms to Social Security. You will need a CMS-40B Application for Enrollment in Medicare-Part B; and CMS-L564 Request for Employment Information. Myers points the public to www.ssa.gov/benefits/medicare/ for those forms.

If you are unable to obtain these forms online, call Social Security at 800-772-1213 and they will mail them to you. You may also be able to ask your employer to print the forms off from the Social Security website.