I'm aware that there are other flights to the East coast ex-FRA that have F (e.g., into EWR, JFK, IAD), but none show availabilty for an award when I need to return. As for returning some miles to me, I'm doubtful US will do that seeing that I have three other legs on this trip in F. Sounds like my best bet is to monitor availability, and if another route with F becomes available, call US and make the switch (expecting that US will waive the $250 per ticket change fee given the involuntary downgrade).