Procedure for transfer of tenancy right in pagdi house

L = Landlord, B = New incoming Tenant/ Buyer and S = outgoing Tenant/Seller. H= Pagadi House located in Dadar, Mumbai, MH Consideration = 100 Situation is as below L, B & S are resident of Mumbai, Maharashtra The Rent receipt are being issued by L in the name of Father of S But Father of S has expired in 2009 S wants to sell the Pagadi House H B wants to Buy the Pagdi House H 1) What is the legal procedure to transfer tenancy rights from S to B. 2) Does S need to surrender H 1st to L and then B will enter into agreement with L(only) OR 3) do all the 3 parties (L,B,&S) need to execute tripartite agreement if yes please provide a general draft format 4) Does such tripartite agreement is valid in the eyes of law if the stamp duty is paid and agreement is registered 5) What if L is not ready to enter into tripartite agreement 6) Does B needs to make 33% payment (100-67) of tenancy premium to L from his bank account or S will make payment to L after B makes payment of 100 to S