Hi FT World...

So it seems I have exactly enough miles to upgrade a LGWHKG segment if I was on a Flex Plus ticket.

Alas, I am only on a Y Flex ticket. I know that I can buy that the additional 15k miles I require and would cost USD600.

Assuming that their was upgrade inventory available, is it a possible to upgrade a fare within a cabin in order to then upgrade to the next cabin?

My rationale is that if the cost of this was USD600 or less, then it obviously makes more economic sense to change the ticket rather than purchase more miles.

Ticket was booked as HKG-LGW-HKG into B class, have already used my outbound segment.

As a side question - this was booked by a travel agent, if I did want to change it, does it still have to changed by the TA, or since I flew the outbound already, the airline has control of the ticket?

Thanks in advance,
Justin/HKG