I've been trying to call for the last 2 hours. When is a good time to call and get a reservation changed?

I would say evening time before things close for the night

Its a very busy resort i would say early morning or after 8 check in usely slows down then.

Usually the best time to call is first thing in the morning around 8:30am or after 1pm. But it can be difficult to get them.

Early morning. Great place