Partner Schedule Change and Reaccommodation

I have an award ticket booked on UA for Turkish Airlines. TK changed one flight time making the connection is IST impossible. What are my rights as far as getting a comparable itinerary? Basically, I could only get rescheduled on flights that had similar award availability (i.e., economy saver) and since the schedule change happened several months after I made the initial reservation, my choices had dwindled considerably.

I actually had a UA agent call TK to see if TK would open another award seat where none existed since it was their change, not mine. No dice.

Cheers.