The first step is to visit your local Planning Department. Rezoning a property can be a tricky thing to do, and you should evaluate if the time and money put into this will be worth it for the property overall.
With that said, here's what you should bring to talk to the counter person at Planning:
The address of the property, the assessor parcel number or map. They will give you the current zoning information including allowed uses and those that require a conditional use permit. If none of these uses are inadequate for what you plan to do, then you should ask to rezone the property.
To rezone a property usually requires you to put together a proposal stating why you want to do this, and a site plan of the property showing the proposed new building. You do not have to have a complete design at this stage, but you should still consider hiring an architect to take you through the process. You will have to fill out an application, pay a fee, notify neighbors (usually up to 300 feet from the property) and you will likely be required to participate in a public hearing. This process can take several months.
To find a local architect, contact your local chapter of the American Institute of Architects (AIA).