10 U.S.C. § 602: Flexibility in determining terms of appointment for certain senior officer positions

The Secretary of Defense may extend or reduce the duration of an appointment made under section 152, 154, 7033, 8033, 8043, 9033, or 9082 of this title by up to six months if the Secretary determines that such an extension or reduction is necessary either in the interests of national defense, or to ensure an appropriate staggering of terms of senior military leadership.