Depending on your financial situation and patience level, you can pursue a conversion to a single-family house. But I would probably only recommend this if you were going to do so for your own purposes. There is nothing to guarantee that you will net more money from selling the building as a house vs two units.
A buyer will need to see a 3BR/building permit history that classifies the property as whichever type of dwelling you are selling. So you can really only sell a building as a single-family home if the 3R classifies it as such.
These are some first steps. Feel free to call me at 415-200-7202.