This is SWA's policy on standby (or changing a flight midstream).
Fares
Southwest Airlines is the nations leading, and largest, low-fare airline. Our unrestricted, generally available fares are typically much lower than the unrestricted fares of other airlines. Our unrestricted fares are fully refundable, have no advance purchase requirements, and enable you to make changes to your travel plans.
We also offer a number of deeply discounted restricted fares ideal for leisure travelers. Plus, we make special fares available to seniors (65 years of age or older), military personnel, infants and toddlers under the age of two years, older children (traveling with adults), and groups of ten or more. And, from time to time, we offer special promotional, sale fares in selected markets and through our web site for online purchases.
With respect to all of its fares, Southwest Airlines does not prohibit or penalize what is commonly known as "hidden city" ticketing, nor does it prohibit or penalize what is commonly known as "back to back" ticketing. "Hidden city" and "back to back" reservations and tickets are authorized for travel on Southwest Airlines.
Furthermore, if you choose not to use a restricted ticket that you have already purchased, the amount you paid for your ticket may, within one year from date of purchase, be applied toward the purchase of another ticket on Southwest Airlines. Your new ticket may, without penalty or fee, be subject to different terms, conditions, and restrictions. We will charge the appropriate fare for the new ticket, which may mean more money, but Southwest does not charge a "fee" for the "exchange" of tickets. No cash refunds or credit card adjustments are made on any amounts paid for nonrefundable tickets.
Fare Rules
All airlines fares vary from city-pair to city-pair. Most discounted, leisure, bargain, or sale fares carry some usage, advance purchase, refundability, and/or stayover restrictions.
If you choose to purchase a ticket that has specific flight requirements and you elect to travel on an alternate flight or flights, it may cost you more money. We do not charge a handling or "change" fee, but an upgrade to a higher fare will ordinarily be applied. This upgrade is the equivalent of the difference between the amount shown on your flight-restricted ticket and the unrestricted fare charged at the time of upgrade for the full itinerary on which you qualify and actually travel.
Tickets for fares that are age-related (seniors, infants, children, students) are sold contingent on the travelers ability to provide proof of age at checkin.
A fare quote is not guaranteed until a ticket is purchased. However, if the fare increases after you have purchased your ticket, we will not collect the difference unless you change your flights, travel dates, or person(s) traveling.
Information and Ticketing
Information regarding all of our current fares, applicable restrictions, seat availability, and other requirements is available 24 hours a day, seven days a week through our Telephone Reservations Center or through our web site, southwest.com.
Our toll-free number is 1-800-435-9792 (1-800-I-FLY-SWA).
En Espanol, 1-800-826-6667 (1-800-VAMONOS).
Customers with hearing limitations can reach Southwest through Teletypewriter (TTY) service at 1-800-533-1305.