Transfer of property.

I need to transfer a property based in Delhi and registered in the name of one deceased Mr SK to my father's name who is the sole legal heir. Mr SK did not have any issues and his widow is willing to provide her consent for the said transfer. My father is the legal heir by virtue of being the only son of Mr SK's sister.

What would be the appropriate process to follow to get the transfer done (gift/release) in case of no will being present? (For additional information, said property has a G+2 structure built on the landlord/pagdi system. We follow islam, if the religion code will come into play). Awaiting your response, Regards.