Originally Posted by irishguy28

Yes, it is standard across the industry that the most restrictive fare applies to the entire journey.

People do not realise this and my guess is that you booked the outbound in the cheapest fare, and paired it with a flexible return, in the belief that you could cancel the "flex" return and end up flying a one-way for the cheapest possible fare. The reason that this rule is enforced (most restrictive rule applies to the entire ticket) is precisely to stop actions like that.

Sorry you didn't know this, but it's a general rule across most legacy carriers (the low cost carriers tend to do things differently)

Originally Posted by irishguy28

Instead of asking them to change a return into two one-ways in the same direction - a very odd ask - why not ask them to change your return into a oneway; then separately buy your own second one-way in the same direction (either after you get your refund, or immediately). (however, if this second "Flex" ticket isn't actually Flex - i.e. the first sector is again in a more restrictive fare family - then you'll run into the same issues as with your first ticket)