Multiple Personalities
If it's true that a living individual must have exclusive access over an asset (body). Then you can do this to a multiple personalities: The one who switch between personalities is a personality, and that guy is the guy. Give that guy a name, it's not the name he would call himself but that's how you call him. Talk to him while he's using a personality. If the personality said "I don't know who you're talking to, or what you're talking about" you said I'm talking to the one who switches between you and the others.