At such date as the City Manager shall determine, each board or commission and each department head shall furnish to the City Manager, personally, or through the Director of Finance, estimates of revenue and expenditures for his or her department or for such board or commission for the ensuing fiscal year, detailed in such manner as may be prescribed by the City Manager. In preparing the proposed budget, the City Manager shall review the estimates, hold conferences thereon with the respective department heads, boards or commissions as necessary, and may revise the estimates as he may deem advisable. (Amended November 7, 2000, filed by Secretary of State February 6, 2001.)