You can cancel an appointment either from the Calendar tab or from the Clients tab (booking history).
Calendar tab
In the Calendar tab, right-click on the appointment you want to cancel
Click "Cancel"
Confirm the cancellation; the appointment will be removed from the calendar.
An email will be sent to the customer to notify them that the appointment was canceled.
If the corresponding time slot cannot be booked anymore, make sure to update your availability or add a busy time slot.
You can see your cancelled appointments in the list view shown below:
Clients tab
You can cancel appointments in the client's booking history tab.
Simply navigate to the client's profile, click "Booking History", then click the appointment you want to cancel.
Cancelled bookings are marked with a red bar, as seen below:
The "Booking History" tab contains a record of all of the client's bookings: past, present and future.