To make online changes to your Southwest Airlines flight reservations Take these actions:
Visit Southwest.com first
Next, select the Edit/Undo tab (above)
To book a flight, provide both your name and your confirmation number (first and last name)
By default, the Edit Flight tab is not selected. Leave it alone as is.
Choose Search from the drop-down menu after that.
Click Choose new flight once you've decided the flight you want to alter. In the event that you have reserved a return trip, the locations of your departure and return will be shown.
After choosing your airline, make any necessary modifications and then confirm.