To Cancel an Appointment:
1. Go to Calendar and click on the scheduled appointment.
2. An Appointment window will open | click on the drop-down menu under Status | select Cancelled | Save.
3. The Appointment has been cancelled. The cancelled appointment will appear on the Calendar screen with the sidebar coloured to grey.
You can also have the option to not display the Cancelled Appointment on the Calendar. Some Clinics actually prefer to remove the Cancelled and No-Shows from the Calendar, to keep their scheduler clutter-free. To enable such a feature of hiding Cancelled Appointments goto Tools | Organisations | Preferences | Calendar | Switch ON, Hide no-shows and cancelled appointments | Save.