Section 202(13)(ii) in The Naval Ceremonial, Conditions Of Service And Miscellaneous Regulations, 1964
(ii)An officer holding acting rank who proceeds on annual leave and on expiry does not return to the same appointment shall retain his acting rank for the entire period of annual leave, provided he continues to be borne against his last appointment for the duration of the annual leave period. No acting promotion shall be made in his place for this period and he shall be struck off the strength of his ship or establishment from the date following that of expiry of annual leave :