You can adjust your travel plans without any cancellation free— including for award tickets — for flights within the U.S., or for international travel originating in the U.S. This applies to most United Economy® and all premium cabin cancellation tickets. You'll just pay the fare difference if your new flight is more expensive. etihad cancellation policy
https://reservationsnumber.org/flight-cancellation/etihad-flight-ticket-cancellation-policy/