Crikey .. I had really hoped someone would be able to report back on HOW this actually works, by now. It should work, it seems a question of getting BAEC to play ball.
As far as I can tell there's a 12,500 avios charge (o/w) for a USA transcon upgrade from AA Economy to AA Biz {presumably its 25k to F on a 2 class transcon?}. The 12,500 avios upgrade situation to a flat-seat Biz looks reasonably tempting.
BAEC T&C say this is possible. So, how to conduct the conversation on the phone?
I'd start off by establishing the reward availability. "Is there any Biz award availability for AAxyz on DD/MM, if so how many avios and fees?"
I'd only then sort out buying the ex-UK ticket with the agent.
If a "no can do" arises, it would be useful to be quoted the para of T&C. Just seems odd posters are reporting BAEC agents don't know how to process this.