Is this a wholesale deal?

[Timothy Reed]

We are buying a property off of my niece that she just inherited. She has agreed on a price is allowing us to rehab and sell it to someone else form a profit. At that time she will take her agreed upon amount and we walk with the rest.  

We are confused on the paperwork. Do we need to have a purchase agreement with an assignment clause or any nodes how to handle this.  We are in Pennsylvania if that is relevant