http://www.flyertalk.com/forum/unite...2015-a-24.html

Call United, you will have better results if you know what you want and can feed them flight numbers. Typically they will pry open award space on UA metal flights if those are acceptable to you. EWR-LIM is operated with a 752 with lie flat seats, I'd ask for that if it were me. IAH-LIM is a 767 also with lie flat but obviously BOS-IAH is a longer flight on a regular domestic 737 versus BOS-EWR.

Refunding is another option, but I'd first try to keep the award together and get the lie flat bird if it were me.