To complete the Application for Medicare Part A and Part B Special Enrollment Period (Exceptional Circumstances) form (CMS 10797) if you are eligible for a SEP for Exceptional Conditions, you should provide documentation of the exceptional condition that qualifies you for the SEP. This may include a letter from a doctor or other healthcare professional, or proof of disability. You should also provide any other required information, such as your Social Security number and the reason for your Special Enrollment Period. The form should be completed and returned to the Medicare Enrollment Center as soon as possible to avoid any delays in your enrollment.