To give an example from the german jurisdiction, if you buy a TV that fell off the truck, you are in posession of the TV but do not have ownership of it (however, you are not required to actually give the TV back, you can do what want with it).

If you sell that TV to a third party, ownership passes to that third party and the original owner looses all property rights on it. One of the few examples where ownership can pass from a party to another without the first party's consent (in neither express or requirement).

I imagine US law isn't totally different there.