Mixed use property zoning

[Nims Varadi]

Dear BiggerPockets community,

I am looking at a mixed use property in Philadelphia which currently has a commercial space on the first floor and three residential units on the second. It has a large lot and I am looking to expand the property by adding more residential units and convert the commercial space to residential units. Does anyone have any experience with a similar situation, any insight into the challenges that may come up, or any advice for putting together a preliminary written proposal detailing plans for the zoning board (the property is not inspected or purchased yet, but when I asked the board if the zoning would allow the conversion they asked for a written proposal). 

Thank you in advance for any insight,

Nims