Section 80. Tenure of commissioned officers

No commissioned officer shall
  be involuntarily discharged or dismissed from the service, unless by the
  senate on the recommendation of the governor, stating  the  grounds  for
  such  recommendation; or by the sentence of a court-martial; or upon the
  findings  of  an  examining  board   appointed   pursuant   to   section
  seventy-five  of  this chapter; or, as provided by section seventy-eight
  of this chapter, for absence without leave for a period of three months;
  provided, however, that a commissioned officer may be transferred to the
  state reserve list or state retired list as provided by  section  twenty
  and section twenty-one of this chapter, respectively.