Both of them must go to traffic dept.Form must be filled ,letter from your sponsor, insurance copy of the car,orginal id of both buyer and seller and registration card(esthimara)sat.open in the morning. If there is loan for vehicle first loan should be closed and NOC from bank should be obtained.Even private party also will do. you should give the orginal id of both buyer and seller and esthimara.They will do it for you.