I assume if the parent consents, a 17 year old can move out. But what type of consent is needed. My sons girlfriends mother is basically physco. One minute she will tell her daughter to leave, then make her come back. If we get written permission from her saying she wants her to leave, will that be enough to stop any runaway crimes? what if she moves out of state with us with written permisson from her parents, then her parents change their mind.