In what Harry Potter book does move out?

It seems like you might be asking about "move out" in the context of Harry Potter, but it's not a specific event or plot point in the books. Could you please clarify your question?

Perhaps you're thinking about:

* Moving out of Privet Drive: This happens in Harry Potter and the Sorcerer's Stone when Harry turns eleven and discovers he's a wizard.

* Moving out of Hogwarts: This only happens in Harry Potter and the Deathly Hallows when Harry, Ron, and Hermione leave Hogwarts to search for Horcruxes.

Could you please tell me which "move out" you're referring to?