Hey
Sorry this question is not as exciting as the thread may sound..lol

Mrs Jock flying in CW Edi-Lhr-Sfo rtn. Bagged a 6 month advanced super cheap deal for just over 1.4k each. Shes flying out earlier than me (8/11/18) to see family..and was kinda annoyed that i manged to UuA into F on my trip but not hers 😉. Its an I bucket fare for the lhr to sfo and I wondered how i could secretly pay cash to upgrade her out bound flight into F...and surprise her..and how much is it likely to cost? unlikely to find another avios seat between now and Nov..so i suppose my options are limited..thxs again.