Watch your reservations for an alert at the top in red. I have a flight at 10:05am in early December for $360, my friend didn't want to pay that much, she booked a 10:35pm for $180. About a week ago, we both got the alert that there may be schedule changes and we could change our flights for free. She switched to the 10:05am for free. So far, both flights are still on the schedule. Today I got it for our return flight (separate reservations). Not sure why they did that.