The head of any state department, except as otherwise provided by law, may assign the functions vested in his or her department to those subordinate officers and employees as may to him or her seem desirable, including the power to appoint a delegate to serve in the director’s place and stead on any of the various boards or commissions to which a director may be appointed. The delegate shall have the same power and authority that would be afforded the director while serving on the board, including the power to vote, provided that the appointment shall be made in writing and shall be filed with the secretary of state. The director may with the approval of the governor establish within the department those subdivisions or other administrative or organization units which may to the head seem desirable in order to expedite the work of the department in the interests of economy and efficiency, and in accordance with good administrative principles and practices. No person other than the head of a department or of an independent agency may challenge the authority of his or her or its agent to do any act which the department head or independent agency is authorized by law to do.