By letter filed with the City Clerk, the City Manager shall designate a City officer or employee to exercise the powers and perform the duties of City Manager during the Manager's temporary absence or disability. The City Council may revoke such designation at any time and appoint another officer of the City to serve until the City Manager returns. If the Council suspends the City Manager, or if there is a vacancy in the office of the City Manager, the Council may appoint an acting City Manager to serve until the City Manager returns, until his disability or suspension ceases, or until it appoints another City Manager, as the case may be. The Council may suspend or remove an acting City Manager at any time by a majority vote of its total membership, not including vacant positions.