The appointment by the court of the Director of Developmental Services as conservator or guardian shall be by the title of his office. The authority of the Director of Developmental Services as conservator or guardian shall cease upon the termination of his term of office as such Director of Developmental Services and his authority shall vest in his successor or successors in office without further court proceedings. The Director of Developmental Services shall not resign as conservator or guardian unless his resignation is approved by the court.