Cal. Elections Code § 2267

(a) If the records of a person designated in paragraph (1) of subdivision (b) of Section 2265 constitute a completed voter registration application, the Secretary of State shall register the person to vote, or, as applicable, preregister the person to vote, unless any of the following conditions is satisfied: (1) The person’s records, as described in Section 2265, reflect that the person affirmatively declined to become registered or preregistered to vote during a transaction with the department. (2) The person’s records, as described in Section 2265, do not reflect that the person has attested to meeting all voter eligibility requirements specified in Section 2101 or, as applicable, all preregistration eligibility requirements in subdivision (d) of Section 2102. (3) The Secretary of State determines that the person is ineligible to vote or, as applicable, will be ineligible to vote when the person reaches 18 years of age. (b) If a person who is registered or preregistered to vote pursuant to this chapter does not provide a party preference, the person’s party preference shall be designated as “Unknown” on a voter registration index under Article 5 (commencing with Section 2183) of Chapter 2, and the person shall otherwise be treated as a “No Party Preference” voter. (c) If the Secretary of State receives from the department pursuant to paragraph (1) of subdivision (b) of Section 2265 the records of a person who is currently registered to vote, the Secretary of State shall use the information in the records to update the voter’s registration information. If the Secretary of State does not receive information for the voter pursuant to paragraph (1) of subdivision (b) of Section 2265 for which space is provided on the voter registration application, but that information was provided in the voter’s previous voter registration application, that information from the voter’s previous voter registration application shall remain part of the voter’s record.