If you are trying to cancel an upcoming appointment you must go to the Appointment feature of the Portal and find your Upcoming Appointments. From there you can cancel any future appointments you may have. But keep in mind, some clinics may impose penalties if appointments are cancelled within a certain time frame. 

1.  Once you have opened the Appointments feature of the Portal you will see any Upcoming Appointments in the main body of the page. Beside this, will be a red Cancel Appointment button. To initiate the cancellation process, click on this button. 

2. After the button has been pressed, you will receive an alert and confirmation that you wish to cancel your appointment. After pressing "Yes, cancel it" you will then be free to book a new appointment that meets your availability.