If an attendee can no longer attend their booking, they can cancel online via the online portal.
After they've logged in, they will see the detail of their upcoming bookings and an option to cancel.
They will need to log-in to the portal, navigate to the booking they wish to cancel and click on the red Cancel Booking button.
All they need to do is click on the Cancel Booking button
The status of the booking will be updated and they will receive an automated email advising that their booking has been cancelled.
If the booking required them to purchase a product, the credit for that product will be refunded back to them, allowing them to re-use that credit on another occasion.
By cancelling, the attendee will automatically be removed from the attendee list of and free up space for other attendees to book.
Also see
Making a booking online