I love Southwest for its ability to check fares and if there is a lower fare on the same flight you are booked on, you can change flight and receive credit. No more. If you attempt to do that, Southweest will not let you make a change. (Same with United). I guess what you have to do is cancel your booked flight and then rebook the same flight with your travel credits. Is this correct? Thanks,
SBT
To your question, I have been able to re-fare and get a credit (or points refunded) whichever the case might be. In the past -If it was a schedule change and I wanted to keep the new flight, but get the refund I would change the flight to a different flight on the same day and then change it back and then do the re-fare as mentioned above.
When you try to make the change, what happens? Does it just say Current flight: 0 for the required fare change (but, you already checked and it currently has a lower advertised fare)?