Section 273(4) in The Naval Ceremonial, Conditions Of Service And Miscellaneous Regulations, 1964
(4)Applications from sailors for transfer from one [rank] [Substitued by S.R.O. 192, dated 10th September, 1973] to another shall be submitted through proper channels to the Captain Naval Barracks for onward transmission to the Chief of the Naval Staff. Applications shall be forwarded only when the man concerned is considered to possess particular aptitude for the new [rank] [Substitued by S.R.O. 192, dated 10th September, 1973] or where there are exceptional circumstances known to his Captain, and in any case the transfer must be recommended as being clearly in the interests of the Service and of the man. The final decision shall depend upon the requirements of the Service in the branches to which transfer is desired.