How are they pulling that off??
They didn't.
We regret to inform you that the 78th Members’ Meeting, which was due to take place on 28-29 March 2020, has been postponed until 10-11 April 2021. We would like to reassure you that your tickets will remain valid for the new date and will automatically roll over, so you do not need to do anything other than hold onto your existing tickets.
The 2020 Goodwood Festival of Speed presented by Mastercard has also been postponed. We are currently exploring potential alternative dates with all relevant parties and would like to reassure you that all tickets will remain valid for the new date.