(1)Where a person in army service enlisted otherwise than on a long-term enlistment his conditions of service may, on written application in that behalf made by him to the competent military authority and with the consent of that authority, be changed as follows, that is to say:—
(a)if his enlistment was for a term ending before the expiration of a period of twelve years beginning with the relevant date, that term may be extended so as to end at such time, not later than the expiration of the said period, as may be specified in the application and so as to increase the period of his army service, his service in the reserve, or both, as may be so specified :—
(b)if the term for which he enlisted, or that term as extended under paragraph (a) of this subsection, includes a period of Service in the reserve, his period of army service may be increased, according as may be specified in the application, so as to extend to the whole or a specified part of that period ;
(c)he may be transferred to the reserve to serve therein for the residue of the term for which he was enlisted, or if that term has been extended under paragraph (a) of this subsection, for the residue of that term as so extended.
(2)A person in the reserve by virtue either of the terms of his enlistment or of subsection (1) of this section may, on written application in that behalf made by him to the competent military authority and with the consent of that authority, at any time re-enter upon army service and, according as may be specified in the application, either—
(a)serve in army service for the remainder of the period for which he would have been liable to serve in the reserve if he had not re-entered upon army service, or
(b)serve in army sendee for a specified part of that remainder and thereafter serve in the reserve for the residue thereof.