GST Practitioner
                
                   55062 Points
                   Joined June 2017
                
               
			  
			  
             
            
             Sorry for above reply
as when the constitution is change or business is transfer then it did not ask for any tax on such transfer, t
(today only I have tried this practically)
Steps to follow
Sir
At the the time of cancellation of firm (father) there it ask for reason for cancellation (under cancellation tab) select the option change in of constitution as soon as u select this option , below it ask u for the Gstn of transfere (son firm) input ur GSTN of Son's firm.
Enter the date from which registration is to be cancelled. next it will not ask for any stock detail to be transferred because only the constitution (PAN) is changed.
lastly OTP will send & submit
(fill all the 3 tabs for sucessful completion)
Enjoy sir without payment of any GST
Actually when there is discontinue of business then it ask for stock details & tax liability therin .
Note : Paper work , Plz prepare a transfer deed