There are four ways that Visitors can sign up for events on your calendar using "Self-Book": Book An Appointment, Group Signup, Make a Reservation, and Suggest an event. When visitors sign up for events on your calendar you can use the "Review Bookings" panel in the "Self-Book" Dashboard to approve or reject the people who signed up. The "reject" option allows you to cancel reservations from visitors who may have signed up, but no longer want to attend your event.
However, you can also give the option to your event attendees to cancel their own reservations. This saves you the hassle of you having to reject their reservation for them. This option is not turned on in the default Self-Book templates, but you can turn it on when you create a custom "Self-Book" template. First, you will need to open a new "Self-Book" template. See the image below:
Once you have opened a new "Self-Book" template you will need to choose the type of "Self-Book" template you want to use and then make sure that the "Allow participants" box is checked before you save your changes to your new template. See below:
If you have both of these boxes checked then the people who signed up for your event will receive an email that their signup was accepted along with a yellow "Click here to cancel or review signup" button at the bottom of the confirmation email. After your attendees' click on this yellow button, a new browser will open. In this new browser, they can then click on a red "Cancel this signup" button. See below:
If the "Booking Processing" in your "Self-Book" template is set to "Always Accept" then any signup cancellations from your event attendees are automatically accepted. However, if the Booking Processing is set to "Hold for Approval" then the cancellation is not automatically accepted and you will need to go into your "Review Bookings" panel in order to approve any cancellations.
If your event attendees pre-paid for your event using PayPal then regardless of what the Booking Processing has been set to the cancellation request is always set to "Pending" until you, as the owner of the event, approves it.