Ok first of all, this is a pain in the ass. You WILL want help for this, or else you'll be looking like a dork like I was doing this.
This first tutorial is to show how to remove the neckpiece on the F60 body and restring it so you can use it with another head.
Note the First: You will want help for this.
Note the Second: Also, I kinda messed up on this leg. You will actually want to tie the knot and leave it towards the torso. DO NOT untie it like I did or hold the knot at the bottom. It makes things seriously difficult.