(a) The officer ordering any military duty shall have the power to excuse any officer or enlisted person for absence therefrom upon good and sufficient grounds.
(b) The Governor, or commanding general of the National Guard with the approval of the Governor, may relieve any organization of the militia on active duty from the further performance of such duty and may order any other organization to perform such duty.
(c) However, the provisions of this section shall not curtail the rights of commanding officers to grant leaves of absence and furloughs as provided by rules unless they are specifically modified by orders from superior authority.