Curious as to others’ views here. This one ended well but had to argue for it.

I was rebooked due to a missed connection. I’d originally been travelling in CE. There was only availability in ET at the point of rebooking so I was given an ET boarding pass for the following morning.

I noticed that a seat in CE had opened up overnight so asked at FW check-in to be moved back into CE. The agent seemed surprised by this request and started talking about calculating a fare difference; I reminded him that the underlying ticket was a CE ticket. He tried to argue that it was ‘a different flight now’ so the original class wasn’t relevant, but I pressed the point and he rang through and ultimately got approval to give me a CE boarding pass.

I’ve had this scenario previously but never had any pushback. A better system would mean that downgraded passengers are automatically moved when seats open up (rather than BA offering them for sale for £500 as was the case here…) but in the absence of that it seems perfectly fair to ask to be moved back.