What kinds of rehabs don't require permits?

[Devin Bost]

I'm considering buying a 6-plex that's currently operating as a non-conforming use. It's currently zoned in a commercial zone that doesn't allow the multi-family rental usage, so if we need to pull permits for any construction to improve the property, the city will reject it unless we convert the unit to a "hotel." 

Unfortunately, the city codes don't specify at all what constitutes a hotel and what makes that different from a short-term residential vacation property, and the folks at the city department aren't returning my calls. So, I'm wanting to know what kind of rehab we actually could perform on the unit to make it more marketable in its current usage so we won't need to convert its use. I've looked into converting the use, but I'm running out of time to make an offer on the property, and the underwriters would need more of a down payment anyway if I wanted to change the use.