@KAOS-
File a non-resident PA return on which you allocate zero income to PA, in order to have the incorrectly withheld PA taxes refunded.
Follow the prompts on the NJ return to claim the credit for the Philadelphia city income tax.
File PA Form REV-419 with your employer to stop the PA state withholding. Here's a link to that form:
https://www.revenue.pa.gov/FormsandPublications/FormsforBusinesses/EmployerWithholding/Documents/rev...
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
