I actually had a similar thing in December of last year. I was flying NS PHL>LAS, and the flight was overbooked. I was in coach for the flight. I asked at the ticket counter if they could re-route me through SAN. They did it no problem, no questions asked. And I even got the bump up to F for both legs of the flight.

As it stands now, I am not in F for the PHX flight, but am for the flight to MEX. Guess I'll have to look at what is available the night before and see if it is worth it and if I have a shot at F for the re-route.