My father-in-law's house property is lying in Chennai. He is no more now. He is inherited by his wife,three daughters and one son.Now we want to build flats through a builder under JDA method. Builder agreed to construct six flats of different measurement. and ready to offer only four flats for us. Mother-in-law is willing to opt out and not ready to accept cash also equal to her share. On the contrary she has advised us to share her portion of cash or land equally. Because of her offer we have gained extra space of area in flats offered by the builder.Now we would like to know how to treat her offer. whether it is treated as Gift and attracts Gift Tax. If so at what rate. PS:Necessary Legal Heir Certificate obtained after the death of my father-in-law.Any Legal Agreement is to be prepared in this regard? At what stage.?