So my girlfriend is over visiting me in the UK and wanted to change her ticket to the 09/01 from 05/26. We got a nasty surprise when they said they wanted $670.00 to do so.

Having made this trip a few times on the midweek days i know that the flights are no where near full and that it seems rather expensive to change, her 2 way ticket was only $560.00.

I understand that she got an economy ticket with more restrictions but is there anyway around this? Can I use my miles to buy a one way fare for her?

Its annoying as we will be making a fair few TA flights between us and I got her to switch to CO from BA, and now she's cursing them.