​​Members with a login can make changes and cancellations online via My Registrations. Cancellations received/processed by May 9, 2021 (Group 1), and by September 13, 2021 (Group 2), are fully refundable. Registrants who cancel after these dates will be issued a refund minus a 50% cancellation fee. Substitutions are accepted. No-shows and registrants failing to cancel prior to June 9, 2021 (Group 1), and October 13, 2021 (Group 2), are responsible for paying the full registration fee. Special events or ticketed item fees are non-refundable. ​If you have difficulty cancelling online, please contact Accounts Receivable at 703-907-6875,, or fax to 703-907-5951.