https://www.integritytoys.com/instructions/bodyswap.html

above please find link to integrity's instructions, I know there are videos out there too and different methods (like heating pad) but be careful with any method, if there are applied lashes (I can't remember if this nat has them eventhough I own her) and protect face and hair from too much or direct heat FYI. need to get head soft enough to safely remove. may need to reheat before placing on your replacement body as it cools quickly.

just a heads up, the older bodies that old can get brittle, so don't be shocked if it breaks and you have to take pieces away, watch out in case sharp edges if that happens. if the neck knob gets stuck inside the head from the rest/neck cracking/breaking, it's not the end of the world if you leave it inside the head, only you will know it's there (rattles, but who cares!). there are ways to remove if that happens but it can be tricky/difficult so not necessarily worth it if you aren't rerooting her or anything anyway.

hope that's helpful