Originally Posted by
Teece
Actually, the biggest issue here is that you can't book a round-trip and only upgrade one leg with OB points, like you can with Avios. It's either book and upgrade a one-way trip ($$$$) or book a round-trip and upgrade both legs. I don't think calling will help, but feel free to try.
I have upgraded one way in the past, but I did indeed have to call and it was a while ago. ISTR that one time a one way upgrade was refused, but couldnt swear to it.