Cal. Elec. Code § 6522

If a selected candidate or an unselected candidate files with the Secretary of State, no later than the 68th day before the presidential primary, an affidavit stating without qualification that he or she is not now a candidate for the office of President of the United States at the forthcoming presidential primary election, his or her name shall be omitted from the list of names certified by the Secretary of State to the county elections officials for the ballot and his or her name shall not appear on the presidential preference portion of the primary ballot.