Any registered voter may make application under oath to change political affiliation by executing a form prescribed by the Secretary of the State Election Board at any time. The county election board secretary in the applicant's county of residence shall process and approve any such application for political affiliation change upon receipt, except as provided in Section 4-110.1 of this title and except during the period from April 1 through August 31, inclusive, in any even-numbered year. The secretary shall process and approve such applications for change of political affiliation received or postmarked from April 1 through August 31 in any even-numbered year after August 31.
Okla. Stat. tit. 26, § 4-119