How do I change the time or date of a reservation

Yoy can cancel an rebook up to 12 hours before a show. After that, you have to call or go by for customer service.

You can't "change" a reservation. You have to cancel and then rebook. Or at least that's what you can do through the mobile app. I don't know if this can be accomplished by calling the staff on site.

And yes you can change your reservation and even cancel. Best to do it the old-fashioned way and pick up a phone and call them. They're very helpful and since most people forget about calling you usually get someone quickly.