Moving out of Pennsylvania is easy. Stopping Pennsylvania taxes is a different act, and it happens on paper: Pennsylvania keeps treating you as a resident until the record shows otherwise.
On the burden of showing otherwise: A person asserting a change of domicile has the burden to prove the change: definite intention to discontinue the former domicile as the primary base of operations, definite intention to make the new location the primary base, and physical presence and abode there. The change dates from the first day of physical presence in the new location.
Two tests decide it. Cross 183 days with a Pennsylvania abode still available and you are taxed as a resident regardless of where you claim to live — and see day-counting rules. Or keep the day count clean but leave the life-pattern evidence pointing at Pennsylvania, and domicile does the same work. Everything on this page exists to answer one question: if DOR asks, does your record hold?