I'd really think hard about relinquishing your present plot. I understand that you really, really want to relocate but if it doesn't work you'll have no house at all and a load of furniture to store. It's also possible you might run into difficulties when you try and buy again.

I did relinquish a personal house recently, having run into an unexpected feature of the new system where one of my characters is flagged because he bought the FC house, so none of my alts can bid on a FC house while he is in that FC. Relinquishing got me nowhere, because his personal house wasn't the issue. I just read the error message saying I owned too many houses and assumed it was.
Last lottery, I got lucky and got him another personal, but storing all his furniture until that happened was a pain and I really missed my house.

Edit: Do let us know how you get on!