((a))
((1)) An officer subject to discharge or retirement in accordance with may, subject to the needs of the service, be continued on active duty if he is selected for continuation on active duty by a selection board convened under .
((2)) An officer who holds the regular grade of captain in the Army, Air Force, Marine Corps, or Space Force, or the regular grade of lieutenant in the Navy, and who is subject to discharge or retirement in accordance with may not be continued on active duty under this subsection for a period which extends beyond the last day of the month in which he completes 20 years of active commissioned service unless he is promoted to the regular grade of major or lieutenant commander, respectively.
((3)) An officer who holds the regular grade of major or lieutenant commander who is subject to discharge or retirement in accordance with may not be continued on active duty under this subsection for a period which extends beyond the last day of the month in which he completes 24 years of active commissioned service unless he is promoted to the regular grade of lieutenant colonel or commander, respectively.
((4)) An officer who is selected for continuation on active duty under this subsection but declines to continue on active duty shall be discharged, retired, or retained on active duty, as appropriate, in accordance with .
((5)) Each officer who is continued on active duty under this subsection, is not subsequently promoted or continued on active duty, and is not on a list of officers recommended for continuation or for promotion to the next higher regular grade shall, unless sooner retired or discharged under another provision of law—
((A)) be discharged upon the expiration of his period of continued service; or
((B)) if he is eligible for retirement under any provision of law, be retired under that law on the first day of the first month following the month in which he completes his period of continued service.
((6)) The retirement or discharge of an officer pursuant to this subsection shall be considered to be an involuntary retirement or discharge for purposes of any other provision of law.
((b))
((1)) An officer subject to retirement under section 633 or 634 of this title may, subject to the needs of the service, have his retirement deferred and be continued on active duty if he is selected for continuation on active duty by a selection board convened under .
((2)) An officer subject to retirement under section 635 or 636 of this title who is serving in the grade of brigadier general, rear admiral (lower half), major general, or rear admiral may, subject to the needs of the service, have his retirement deferred and be continued on active duty by the Secretary concerned. An officer subject to retirement under section 635 or 636 of this title who is serving in a grade above major general or rear admiral may have his retirement deferred and be continued on active duty by the President.
((3)) Any deferral of retirement and continuation on active duty under this subsection shall be for a period not to exceed five years, except as provided under section 1251 or 1253 of this title.
((c)) Continuation of an officer on active duty under this section pursuant to the action of a selection board convened under is subject to the approval of the Secretary of the military department concerned. The period of the continuation on active duty of an officer under this section may be reduced by the Secretary concerned in the case of any officer as provided in .
((d)) For purposes of this section, a period of continuation on active duty under this section expires or is completed on the earlier of (1) the date originally established for the termination of such period, or (2) the date established for the termination of such period by any shortening of such period under .
((e)) The Secretary of Defense shall prescribe regulations for the administration of this section.