What is the procedure to join/revert back to parent department in lien (Technical resignation ) ?

My friend previously worked in autonomous body applied to a post of higher grade pay in central govt through proper channel and got NOC , he was selected to the applied post in new department. Then he applied his technical resignation with lien through proper channel to the office where he was working , His Technical resignation with lien was accepted by his Head office and he was relieved from branch office (where he was working ) .i got a letter from Head office " mentioning as Techniacal resignation with Lien was Approved". The problem here is In his relieving letter there is nothing mentioned about his lien but they quoted the Head office's technical resignation order no. In my Technical resignation order given by my Head Ofice , It was written as Technical resignation with lien but my relieving letter only technical resignation . Here i am in confusion whether i was given lien or not ? and one more question is that how to revert back to parent department in lien, is there any particular procedure to be followed ? if so How to write a letter to present department to revert back to parent department by exercising lien of technical resignation , In that letter can i write the word resignation or repatriation ?