California Code, Government Code - GOV § 18950

(a) Vacancies in positions shall be filled insofar as consistent with the best interests of the state from among employees holding positions in appropriate classes, and appropriate promotional lists shall be established to facilitate this purpose, except as provided in Section 18930. Examinations shall be held on an open, nonpromotional basis when, in the judgment of the department or designated appointing power, open competition will produce eligible lists with more highly skilled qualified candidates and is consistent with the best interests of the state.

(b) Consistent with board rules, the department may prescribe conditions under which state employees, persons on leave of absence, and persons whose names are on appropriate reemployment lists, may be permitted to compete in promotional examination and to attain eligibility for appointment.

(c) The department, consistent with board rules, may prescribe conditions under which eligibility may be transferred from one promotional list to another promotional list.

(d) Notwithstanding subdivision (c), eligibility may not be transferred from one promotional list to another promotional list where the list to which eligibility has been transferred is for a classification requiring specific professional licensing unless the applicant possesses the appropriate license.