Navigate your way to Classes/Appointments >> Class Types >> and select your desired class.
Click the gear icon beside the timeslot you would like to remove, and click 'Cancel'.
Then click Cancel Time Slot:
Note. If there are classes with attendances i.e. customer/s are registered onto, then you will have to cancel these manually, by clicking the cancel option.
From the subsequent page, you have the option to refund the customer, and notify the customer/s of the cancellation. Once you have made your choices, you can click to cancel the class.
Repeat this process for any classes with attendances. Once complete, click the gear icon beside the timeslot you would like to remove, and click 'Delete'.