Cancellation

W are not Apple employees, rather end users like you and cannot do anything about appointments. You'll need to call the store or start with this link:

Apple Store - Find a Store - Apple

Hopefully that will lead to a link for your country. Once you identify the store you should be able to find the cancel function.

https://www.apple.com/au/retail/geniusbar/

select your store.

The next screen has change or cancell a reservation.

We are not Apple. We are users like you. If you want to contact Apple call the store and let them know.