I need to cut the centers from my wheels...

[Tx Firefighter]

Those are just spotwelds. No reason you can't remove them yourself. Since you're trashing the outer hoops, you can use a grinder to dig down into them from the outside. When you get close, use a mallet to whack the center disc periodically. When you get the spot welds ground out sufficiently, you'll be able to dislodge the centers from the hoops. Then take them, along with your new hoops, to the wheel shop.

Personally, I have done them myself before. I got them fitted up and bolted to the truck then mounted a dial indicator and spun the wheel as I tack welded until they were firm and then removed and stitch welded.