The hook here is that you can change classes at any time, and you're encouraged to do so to make the most of your efforts. (snackbar-games.com)
You either belong to a «class» and can't change your class, or classes don't exist, only pay bands for specific jobs. (politics.stackexchange.com)
Please note our cancellation policy: In order to change your class date without penalty a 48 hour or more notice must be given to cancel or change the selected class date. (centurydriving.com)