Appointments cannot be deleted from any other status except for cancelled. If you want to delete an appointment, first take steps to mark it as cancelled and then you'll be able to follow the directions below to delete it from your appointment logs.
To delete an appointment or a set of appointments, all I need to do is go to Appointments → Appointment Lists → Cancelled and select the appointments I would like to delete using the left hand checkboxes:
After selecting the appointments I want to delete, I just press the Delete button which will display a confirmation window where I can confirm that I'd like to delete the appointments I selected:
If you delete an appointment by accident you may contact your account administrator to ask him/her to restore it.