The Secretary of a Military Department to whom the Secretary of Defense or the Deputy Secretary of Defense has assigned administrative and logistical support of the headquarters of a combatant command, United States Element, North American Aerospace Defense Command, or subordinate unified command. The nature and scope of the combatant command support agent responsibilities, functions, and authorities shall be prescribed at the time of assignment or in keeping with existing agreements and practices, and they shall remain in effect until the Secretary of Defense or the Deputy Secretary of Defense revokes, supersedes, or modifies them. (DODD 5100.03)