Originally Posted by
TonyHancock
The MMB feature on the RJ site will also allow you to change FF numbers.

It does, just be a little cautious of using that one, RJ has a nearly raw interface into Amadeus. I would use the other options first, which ironically also includes Qantas as well as Qatar and Finnair, then RJ as a last resort. Well, one could always telephone BA or your travel provider...