Locate the appointment you need to cancel in the Upcoming Appointment list.
Click on the trash can icon next to the When date
You are presented with the option of sending the student an email, and a chance to give an explanation to the student regarding the cancellation. Then click on Cancel Appointment.
A cancellation email is sent to the student at this point (if you have checked the box).The appointment will come out of your Outlook and LibCal calendar. You will not receive an email as you have initiated the cancelation and therefore know about it.