Complete the new owner information on the back of the certificate and sign it. Bill(s) of sale, if needed to establish a complete chain of ownership.You ask the California DMV. Things like titles and bills of sale are normally required to prove legal ownership. You will need the reg 227 if no title is available. The registered owner (her) will need to fill out sections 1,3 and 4. Important to have but not needed at DMV. Properly filled out title trumps BOS. Transfer, Replace, or Change Title To prove vehicle ownership, it's important to have a valid, up-to-date, and accurate Certificate of Title. We will always need to know that you are the legal owner of the vehicle.