Originally Posted by
destere
Thanks for the replies. Apologies for not being clearer - I do mean paying he fare difference in money. Either PE or J, depending on the fares. However it seems that there is no way to do this on a O fare. Oh well! Y is Y, but at least Cathay make a decent job of it!
CX probably won't even allow you to upsell to a higher economy class so your chances of getting into PE or J is zero percent even if you want to pay the difference. Best you just buy a new ticket.