To cancel genius bar reservation:
Begin by scrolling down to the bottom of the Apple homepage to find the Genius Bar option and click on it.
Then scroll down to find either Software support or Hardware support, depending what you booked your reservation under, and click on one of the two.
Then scroll down to find "See your cases and Repairs" ( at Contact Apple Support ) and select.
Enter your repair ID or Case ID with which you were provided when booking the reservation.
This will take you to a summary of your reservation in which you can Reschedule, Cancel or Cancel for another solution. Select Cancel.