How can a 13 year old legally move out of their parents house and live with a family member if they are not happy at home?

It is not uncommon for a 13 year old to be unhappy at home. That is actually quite a normal part of being 13. That does not mean the parents are doing anything wrong. For a 13 year old to legally move out, the parent would either have to give up custody, assign guardianship, or be proven unfit and a court order be issued. The laws will differ per state, but we did have legal guardianship over a minor family member. By the father giving us guardianship, we were responsible for the minors actions, we were able to enroll her in school, seek medical treatment, and make other decisions. However, the father also kept all of his custodial rights.