Rera applicability for redevelopment of housing society

Dear all I need expert opinion in Redevelopment of Housing society 1)My flat in Mhada building now convenience deed is done and land on society name. 2)Builder approach for redevelopment and saying RERA is not applicable for redevelopment case 3)Also while making agreement with builder is need to involve MHADA , so builder is also answerable to Govt authority.