​Members with a login can make changes and cancellations online via > Member Center > My Registrations. Cancellations received/processed by March 26, 2019, are fully refundable. Registrants who cancel after this date will not receive a refund. Substitutions are accepted. No shows and registrants failing to cancel prior to March 26, 2019, are responsible for paying the full registration fee. If you have difficulty cancelling online, you may contact Accounts Receivable at 703-907-6875, or fax to 703-907-5951.