I was wondering if anyone else has experience with this issue. I had a set of 4 flights booked as a multi city trip in flexible economy back during the double status credits promotion. I called up Qantas because I wanted to change 1 of the flights (the 2nd one) to another date (about 10 days later, total trip is 5 weeks), but the person on the phone kept saying he couldn't do it or find anything for the dates I wanted to change to. It was a bit hard to understand what was going on because he kept mumbling, but he kept saying things like "can't get combination" and "needs to be in the same class". The whole point in buying flexible economy was that I wanted to be able to change flights without a fee if necessary. Does anyone know why this is so difficult? Would it have been better to avoid the multi city and buy and instead buy a return trip inside a return trip? Are they unable to simply look up an equivalent flight on a different say for just that 1 flight, or do they have to run the entire algorithm of 4 flights every time they want to test a new date? Thanks for your help.