Regarding mutation or transfer of the property

Hi. I have a property of 200 gaj of my maternal grandfather .. according to his will now my grandmother is the owner of property. Now she wants to transfer the property in my name (my mother is adopted).........but only 62 gaj property is mutated out of 200 .. how is it possible because i have registry of 200 gaj with 65 years chain... kindly suggest what to do in this case..how to do registry in my name or mutation done the whole property in my name