By default, only admins have access to reschedule or cancel appointments, but if you want your customers to have this ability, you can enable it on our premium plan or above.
Using this feature you can also allow your customers to Reschedule and Cancel appointments. Also, you can set specific timelines, on cancellation and rescheduling appointments and only have them cancelled, 3 minutes, 3 hours or 3 days before the appointment. Post which, the customer wouldn't be able to make changes.
Head over to: Appointo > Appointments > Manage > Show > Scroll down and check the box next to - Allow customers to reschedule/cancel bookings > Enable the check-boxes > Select the timeframe > Save the configuration and you will be good to go.
Here’s a short-video to help you with all the steps: