Southwest question on lower fares

[Jimdamedic]

We are going to in December. We live nearly in the middle between St. Louis and Chicago. We would really rather fly from St. Louis. If I book airfare from St. Louis and Chicago comes open much cheaper, can I switch the flight and still get a credit for a future flight. Or, if I book St. Louis am I stuck flying from there no matter what.

Also, if a cheaper price comes out, is it a big pain to rebook the airfare to get the credit?

Thanks for the help.

 

[Chip 'n Dale Express]

One thing I love about Southwest is that you can change your flight, and the only thing you have to pay is the difference in the flight. And if the flight is cheaper, then you get a credit towards the difference