Cal. MVC § 228

(a) A commissioned or warrant officer of the California National Guard who has served 20 years in the active service of the state may, on application, in the discretion of the Governor, be retired. Service in the United States Army, United States Air Force, United States Navy, or any reserve component thereof is considered state service in computing length of state service for the purposes of this section.

(b) Upon application made within one year of retirement, the officer may, in the discretion of the Governor, be granted an honorary advancement to the next grade above that held on the date of application for retirement. The Adjutant General shall adopt regulations governing the application procedure, qualifications required, and rights and privileges in connection with honorary post-retirement promotions under this subdivision. If recalled to either state or federal active service, a person honorarily promoted under this subdivision shall return to duty in that grade specified by federal law or regulations applicable to the person.

(c) Commissioned and warrant officers on active duty with the office of the Adjutant General pursuant to Section 167 who are not members of the Public Employees’ Retirement System and who have been on active duty with the office of the Adjutant General for a total of 10 years shall, on application, be retired in accordance with the federal law and regulations which on the date of application govern the retirement of commissioned and warrant officers of the reserve components of the Army of the United States on extended active duty. Retirement from state active duty with the office of the Adjutant General does not prohibit a person from active service in the California National Guard. In these cases, the length of service shall be computed as provided in this section and Section 215.