To change a Southwest Airlines flight, 1-833-426-5533 or 1-833-426-5533 you can do so online or via the mobile app up to 10 minutes before your original scheduled departure time. There are no change fees, 1-833-426-5533 or 1-833-426-5533 but you will pay the difference if the new flight is more expensive. Yes, 1-833-426-5533 or 1-833-426-5533 you can change a Southwest flight for free up to 10 minutes before departure,