39 U.S. Code § 205 - Procedures of the Board of Governors
(a) The Board shall direct and control the expenditures and review the practices and policies of the Postal Service, and perform other functions and duties prescribed by this title.
(b) Vacancies in the Board, as long as there are sufficient members to form a quorum, shall not impair the powers of the Board under this title.
(c) The Board shall act upon majority vote of those members who are present, and any 6 members present shall constitute a quorum for the transaction of business by the Board, except—
(1) that in the appointment or removal of the Postmaster General, and in setting the compensation of the Postmaster General and Deputy Postmaster General, a favorable vote of an absolute majority of the Governors in office shall be required;
(2) that in the appointment or removal of the Deputy Postmaster General, a favorable vote of an absolute majority of the Governors in office and the member serving as Postmaster General shall be required; and
Source(Pub. L. 91–375, Aug. 12, 1970, 84 Stat. 721.)