39 CFR § 4.1 - Chairman.
(a) The Chairman of the Board of Governors is elected by the Governors from among the members of the Board. The Chairman:
(1) Shall be elected at the Board's regularly scheduled annual meeting for a term that commences on December 1 of the calendar year in which the election occurred, or upon the death, departure or resignation of the current Chairman, whichever occurs first, and expires upon the election and installation of a successor Chairman;
(2) Shall preside at all regular and special meetings of the Board, and shall set the agenda for such meetings;
(3) Shall select and appoint the chairman, vice chairman (if any), and members of any committee properly established by the Board.
(b) If the Postmaster General is elected Chairman of the Board, the Governors shall also elect one of their number to preside during proceedings dealing with matters upon which only the Governors may vote.
(c) In the event of the Chairman's death, departure or resignation prior to the election of a successor, the Board, as soon as practicable, shall elect a new Chairman who shall serve a term that commences immediately upon election and expires upon the election and installation of a successor Chairman.