Welcome Newflyer789, to both Flyertalk and the BA forum. It's good to see you here, thank you for joining up with us, and I hope that we get to see plenty more of you in the very near future.

The short answer is no, it can't be done. And that's pretty much the long answer too. It's easier to get a divorce than get BA to change your membership dates. The one well known concession is that if you are short of TPs at your year end, they will take into account any travel in the following 2 weeks by way of extending your year. And that pretty much is all the flexibility you can expect.