I was unable to change to a different flight on their website or via multiple phone calls due to AV's lack of customerservice support and anysmal website. I finally received a call from AV <24 hours before the flight confirming the "new" flight details, and at that point, there was not an option to switch to any of the other flights. I ended up flying on a nearly empty AV11 that departed the same day and time as the 22 Dec AV11 completely booked flight (leading to a very hectic airport sprinting experience to find the correct AV11).