22 USC 2695 - Administrative services

(a) Agreements 
Whenever the head of any Federal agency performing any foreign affairs functions (including, but not limited to, the Department of State, the Broadcasting Board of Governors, and the Agency for International Development) determines that administrative services performed in common by the Department of State and one or more other such agencies may be performed more advantageously and more economically on a consolidated basis, the Secretary of State and the heads of the other agencies concerned may, subject to the approval of the Director of the Office of Management and Budget, conclude an agreement which provides for the transfer to and consolidation within the Department or within one of the other agencies concerned of so much of the functions, personnel, property, records, and funds of the Department and of the other agencies concerned as may be necessary to enable the performance of those administrative services on a consolidated basis for the benefit of all agencies concerned. Agreements for consolidation of administrative services under this section shall provide for reimbursement or advances of funds from the agency receiving the service to the agency performing the service in amounts which will approximate the expense of providing administrative services for the serviced agency.
(b) Payment 

(1) A Federal agency which obtains administrative services from the Department of State pursuant to an agreement authorized under subsection (a) of this section shall make full and prompt payment for such services through advance of funds or reimbursement.
(2) The Secretary of State shall bill each Federal agency for amounts due for services provided pursuant to subsection (a) of this section. The Secretary shall notify a Federal agency which has not made full payment for services within 90 days after billing that services to the agency will be suspended or terminated if full payment is not made within 180 days after the date of notification. Except as provided under paragraph (3), the Secretary shall suspend or terminate services to a Federal agency which has not made full payment for services under this section 180 days after the date of notification. Any costs associated with a suspension or termination of services shall be the responsibility of, and shall be billed to, the Federal agency.
(3) The Secretary of State may waive the requirement for suspension or termination under paragraph (2) with respect to such services as the Secretary determines are necessary to ensure the protection of life and the safety of United States Government property. A waiver may be issued for a period not to exceed one year and may be renewed.