To cancel an appointment click on an appointment in the calendar view. You can make the updates and save the changes.
From the left hand navigation select Appointment and in the sub menu select Calendar.
Type the name of the customer or the pet for whom you want to edit an appointment. The current month calendar for the selected customer will be populated. Click on an appointment in the calendar which will bring up the view appointment detail form.
Click on Delete button to cancel the appointment. If it is a reoccuring appointment then it will give you an option to delete all the appointments or just the specific instance. You also have option to send an e-mail to the customer for the cancellation.