Since ticket policies are up to the organizer's discretion, organizers are responsible for approving and processing a date change from their Stellar Dashboard.
Locate the customers transaction by searching their email address using the "Customer Email" field at the top of your dashboard.
2. Their customer record will appear in the search results. Click on their email address to access their profile, or on the last purchase date to access their customer data.
3. If you're okay with the date change, on the transaction page scroll down to where it says Tickets and click revoke next to the customers ticket. This doesn't refund the transaction, it simply invalidates the ticket link to the existing date and adjusts the total of tickets sold/issued for that performance.
4. Once you've revoked their ticket, you can now issue them a new ticket for their preferred performance.