Right now, Southwest Flight Change one of the best flight change policies I have ever seen. Between certain dates, you can change your flight for free AND not have to pay the fare difference!

Southwest Airlines flight change rules

• When you change your flight on the day of departure, the same rules apply as if you changed your flight weeks or months before.
  At Southwest, if there is a fare difference between what you paid for your reserved flight and your desired new flight, you nearly always have to pay the difference.
• Nevertheless, you will not be asked to pay an additional fee on top of the fare difference.
• Those traveling on full-fare tickets may have to pay little or nothing to change their reservations. Ditto those who want to change a discounted fare reservation while discounted seats are still available.
• The problem comes if you want to change a discounted reservation when discounted fares have sold out. This fare difference may end up being more than the change fees charged by other airlines.
• Happily, though, Southwest Airlines Reservations Roundtrip prices are actually two one-way fares. That means that you pay only the difference on the portion of the reservation you are changing.
• Although it will not waitlist you in advance for full flights, Southwest standby allows you to show up at the gate. The agent will confirm with you if he or she can. You will be asked to pay any fare difference.
• Use your existing boarding pass to go through security and then head for the gate of the flight you want. As with other airlines, elite Southwest Airlines' frequent flyer members have priority over you.
• Even if a flight shows no seats available, travelers miss connections, do not allow enough time for security, or simply fail to cancel reservations that they will not use. A totally booked flight does not mean that you will not get on.