Neither the City Council nor any of its members shall instruct or request the City Manager, or any subordinate of the City Manager, to appoint to or remove from office or employment any person except with respect to those offices which are to be filled by appointment by the City Council under the provisions of this Charter. Except for the purposes of inquiry and investigation, the City Council and its members shall deal with the administrative service of the City solely through the City Manager and shall not give orders to any of the City Manager’s subordinates, either publicly or privately.