The Late VX105 Yes, that's what should happen, of course, and you have shown that it's perfectly possible if someone in charge thinks ahead.
Enough of that; here's some praise for a superb response by an airline in a situation where others might have responded quite differently.
Step forward Flybe.. For the first time in my life I made a stupid mistake a few days ago when booking myself and a colleague onto a day return pair of flights. The result was that I had two seats, and the colleague none.
Customer Service picked up the phone in about 10 secs, listened to my tale of woe, and asked; "What's the other passenger's name?". I told her, and she said "No problem, it was obviously a mistake, I've changed the name and there's no charge."
I'll be back. In this day and age, we've learned not to expect that, and we should treasure it when it happens.
Mind you, she did add, very sweetly; "Do you need anything else, like assistance to the aircraft?", and I'm still wondering about that. I think it means that Flybe's staff have retained a good sense of humour, and I love it.