(a) The Secretary of the Army may, upon the officer‘s request, retire a regular or reserve commissioned officer of the Army who has at least 20 years of service computed under section 7326 of this title, at least 10 years of which have been active service as a commissioned officer.

(b)(1) The Secretary of Defense may authorize the Secretary of the Army, during the period specified in paragraph (2), to reduce the requirement under subsection (a) for at least 10 years of active service as a commissioned officer to a period (determined by the Secretary of the Army) of not less than eight years.

(2) The period specified in this paragraph is the period beginning on January 7, 2011, and ending on September 30, 2018.