Can I have a lot rezoned after the seller has had it inspected?

[Junior Francica]

Hello everyone. This is my first post on here so thank you for helping me out. 

There is a piece of land for sale that I am interested in to possibly purchase and a build a single family or duplex on. I called and spoke with the Realtor and he said the current owners had the property zoned (not sure thats the correct lingo) and it came back saying that it could only have 1 bedroom and about 900 sqft on the lot. 

The lot size is .23 of an acre. My question is, can it be rezoned somehow or make it to where I can have more rooms built on the lot? 

Across the street from it, there is a duplex and tri plex and single family homes around it so not sure why it was zoned with only 1 bedroom. 

The realtor said the seller might be willing to do a seller financing and since I don't have the capital to purchase something right now I am trying to figure out if I can at least get the lot and re-zone it. 

Thanks for the help.