Cal. Elections Code § 3016.5

(a) A voter may vote their vote by mail ballot, without the identification envelope, in person at the office of the county elections official, a satellite location, the polling place designated for the voter’s home precinct, or a vote center established pursuant to Section 4005, if all of the following conditions are met: (1) The county elections official or their staff, including any staff managing a satellite location, a precinct board, or a vote center election board, as applicable, has real-time access to the county elections official’s election management system, and does both of the following: (A) Verifies that the voter has not returned a vote by mail ballot for that election. (B) Changes the status of the voter in the election management system from a vote by mail voter to an in person voter. (2) After the voter’s status has been changed pursuant to subparagraph (B) of paragraph (1), the voter provides their name, address, and signature pursuant to Section 14216. (3) The county elections official has established procedures to ensure that a voter who casts a ballot pursuant to this subdivision does not submit more than one vote by mail ballot without the identification envelope, and the precinct board or vote center election board complies with those procedures. (b) A ballot cast pursuant to subdivision (a) shall be processed and counted in the same manner as a nonprovisional ballot cast in person at the polling place or vote center. (c) The elections official shall provide notice of any satellite location not later than two weeks before voting may occur at the satellite location.