Originally Posted by christep
This is really annoying for people who want to upgrade long-haul segments on L/DONEn tickets that are still often issued on paper (e.g. by EMECO in Cairo)
You can't upgrade BA for oneway flights anyway! So the only exception to the above rule is maybe BKK/SIN-SYD/MEL-SIN/BKK and LHR-DXB-LHR.
Then for economy tickets ex-various cities, you'd have to start issuing them through CX instead of AA!