What is southwest airlines flight change policy With Southwest Airlines, changing a flight is a rather simple and hassle-free process. The absence of a fine is the best part. There won't be any charges thanks to Southwest's change policy! Only one need remains: you must let us know about the change at least 10 minutes before your departure time. If you made your flight reservation online, follow the same steps to alter it. Southwest must be contacted if you made your current flight reservation over the phone.