Originally Posted by spanners
I had to do the opposite thing, book seats on UA metal when I booked through BMI (miles and cash award). I found that using the references shown on the 'checkmytrip' itinerary (accessed using the BMI booking reference, I'd hope it would be similar for a UA reference) UA where able to book seats months in advance. ^
Worth a try, good luck.
Unfortunately I can't pull up a united itinary on check my trip or anywhere else for that matter. I'll give BD a try for what its worth and if this doesn't work I'll go back to UA as they seemed to be able to reserve me an aisle seat in the first place. Failing that I'll have to try my luck at check in.