You can easily cancel or reschedule a booked live online class. You can do this up to 2h before the class is scheduled to start, after that (if you have 1x or 5x class credits) you will have lost the credit.
Log in on the website and go to your profile
Select My Bookings. You see all your booked classes listed with a link to Zoom, to Cancel and to Reschedule
If you want to cancel now and book again later, just click cancel. If you do this on time, your credit will be returned to your credit balance.
If you already know when you want to take the class instead, click reschedule and choose the new class time straight away.
You can also do this on the mobile Wix app, just click your profile badge and then My Bookings.