Hopefully, Medicare eligible IBM retirees already selected and enrolled in replacement medical and part D plans by the end of 2013. If not, there is still time for some people to do it. I say "some" because there is a "Special Enrollment Period" (SEP) in 2014 but only for people whose plans were terminated. For example, if you were using plans that terminated at the end of 2013 such as the IBM medical supplement plan, IBM prescription drug plan, IBM medical supplement and prescription drug plan, or Aetna Integration plan you have until the end of February 2014 to get a replacement plan without any Medicare penalty or preexisting condition underwriting and you will be able to get your IBM HRA subsidy.
There is a Medicare Advantage disenrollment period that Medicare offers at the beginning of every year from January 1 - February 14. During this time Medicare allows people to change from a Medicare Advantage plan to Original Medicare and get a part D plan. HOWEVER, if you do so, you MIGHT not be able to get an insurance company to sell you a medigap plan if you want one. This is called guarantee issue rights. State laws regarding medigaps come into play as well other factors. Make sure you determine your eligibility before you drop your Medicare Advantage Plan. Also, you risk losing access to your IBM subsidy unless you buy a part D or medigap plan offered by Extend Health when you make that change (unless your spouse still has a EH offered plan).
There is an SEP that exists for the entire year that allows you to switch to a 5 star rated plan once during the year. Again beware - if the 5 star plan is not an EH plan you will lose your subsidy when you make the change.
Medicare law regarding SEPs is complicated and it is easy for Medicare agents, Extend Health agents or non-profits to make mistakes when telling you your rights. Be sure you ask multiple people, multiple times about your options. Here is a link to a document that describes various SEPs: