Any construction consists of 2 most important factors first is b.up area & 2nd is land on which building is constructed. After completion of construction builder/developer was supposed to transfer land in name of society (or association of apartment). This transfer process is called as conveyance deed. A survey shows that in almost 80% society this process was not completed. Hence in government record land is still in old owner's name. When society needs redevelopment permission / modification permission, land must be in name of society.
Once a minimum of 60% flats in the project are sold, as per mofa-1963, the builder is expected to form a housing society or association of apartment of these flat owners. And hand over the entire ownership of the land, amenities & other structures (if any) in name of the society. With this, the ownership record of the land or the 7/12 extract of the revenue department, bears the name of the housing society and the name of builder or previous owner is removed. This transfer of rights is called execution of the conveyance deed and with it; the role of the builder comes to an end.
A cooperative housing society is registered if it has a minimum of 10 flats. The conveyance deed is not issued in the name of an individual. A flat owner while buying a flat from a builder takes only a purchase agreement. He thinks that he owns the flat as well as the land on which the housing scheme stands, but that is not the case. The housing society should have a conveyance deed to the legal owners of the land; otherwise the builder continues to be the legal owner of the land. Such transfer of rights is required for changes like construction, removal of some property; some space or infrastructure is to be rented, reconstruction or redevelopment. If FSI of that area is increased, society can do additional construction, only if conveyance deed is in favor of society.