The educational service district superintendent may appoint with the consent of the educational service district board assistant superintendents and such other professional personnel and clerical help as may be necessary to perform the work of the office at such salaries as may be determined by the educational service district board and shall pay such salaries out of the budget of the district. In the absence of the educational service district superintendent a designated assistant superintendent shall perform the duties of the office. The educational service district superintendent shall have the authority to appoint on an acting basis an assistant superintendent to perform any of the duties of the office.