It is a few years since I was at AAA, but some of the staff had administrator access to the online booking system and could move or cancel bookings. This was usually done if an aircraft went tech (often!) and an instructor needed an aircraft.
The important thing is to stand up for yourself but also be fair to others.
There is some fantastic flying to be had from Gillespie:
Local flights around the mountains and reservoirs
Palm Springs (take swimming trunks - there is a pilots pool!)
Santa Monica (before it closes) via LAX overhead
Borrego Springs
Big Bear (take an instructor)
Catalina Island (not done it myself, maybe next time)
Las Vegas (overnight, if permitted)