Originally Posted by
escapefromphl
That was a no, no change on the LH segment so they were only willing to entertain changes from where UA flights took over.
That's unfortunate. I'd be tempted to HUCA unless FRA-SFO somehow arrives later than your existing flight. Generally a rebooking under these conditions is pretty much automatic, although I guess I've heard the "we have to keep the same partner airlines" nonsense a few times before.