Procedure for name change in all gov. documents

Dear Sir/Madam, Subject- Advice on Name correction/change case In our community we use both “Varma and “Kashyap” as surname. My brother’s name in all his documents is “Nil Sagar Varma”; we are four brothers and the remaining three of us have “Kashyap” as surname. Our father also has “Kashyap” as his surname in all his documents (Our Father’s Name- Keshab Nath Kashyap). Now my brother wants to correct this mistake and wants his name to be modified as: “Neelsagar Kashyap” instead of “Nil Sagar Varma”. Existing records in his documents: Name- Nil Sagar Varma Father’s Name- Keshav Nath Varma Modified records needed: Name- Neelsagar Kashyap Father’s Name- Keshab Nath Kashyap (Note the difference B and V in KESHAB) If there are too many complications in the above case he also agrees to keep his name as below (that is, opting for only replacing Varma with Kashyap and leaving other portion of the name as earlier): Name- Nil Sagar Kashyap Father’s Name- Keshav Nath Kashyap Please guide me