Log in on their website and check your bookings at least weekly. If there is a change they will not notify you until about 1 month before your flight. If you check yourself, you will be able to call the 800# and they will make whatever changes you need before the plane is full. You definitely want to check though because even though your flight may only be changed by a few minutes, it could be going from a nonstop to a stop or needing to get on another plane.