Customers can modify their own bookings up until the change deadline you have set.
To update a booking internally, open the booking and click the booking reference button. Select Change and choose what you want to update. The booking updates automatically, and the customer receives an email confirmation.
Quantities can also be adjusted in the booking dialog under Change Quantity. This feature becomes available a set time before the visit, configurable under Settings → Check-in.
Note: Once a booking has been checked in, it can no longer be modified. All changes must be made before check-in.