If more than one voter requests a recount of the same office or measure pursuant to Section 15620 or 15621, and at least one request is for a manual recount, the county elections official of a county subject to multiple requests as described in this section shall conduct only one manual recount of the ballots subject to recount, the result of which shall be controlling.
Source:
Section 15621.5, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=ELEC§ionNum=15621.5..