I had a flight change on a mileage run from pvd-dtw-atl-msp-san Due to schedule changes they added another segment for me going dtw-mem-atl-dtw despite the fact they had direct dtw-atl flight that would have gotten me there sooner. NW is usually pretty helpful when reacommodating.
What I hate is having the NW rep quote each of the stories I give them as to the reason I need a flight change - keys clacking away in the background give me a chill.