 It is also possible that a former employer or union might sponsor a Part D plan for former employees/members (such plans are called Employer Group Waiver Plans).Medicare beneficiaries can enroll directly through the plan's sponsor, or indirectly via an insurance broker or the exchange—called Medicare Plan Finder—run by the Centers for Medicare and Medicaid Services (CMS) for this purpose; the beneficiary's benefits and any additional assistance payments and rights are the same regardless of enrollment channel.Beneficiaries already on a plan can choose a different plan or drop Part C/D during the annual enrollment period or during other times during the year under special circumstances.