Allocation of New York Wages for a New Jersey Resident working Partly at Home

I have a granddaughter who is employed by a New York City employer.  She works from home in New Jersey part time.  Her W-2 form from her employer shows all of her wages being New York sourced.  Does she need to get her W-2 amended, or can the allocation to New Jersey be defined in TurboTax itself. And, if so, what is the procedure?