Change birth certificate name

Dear Sir,

My name is Ankur Patel live in Surat(Gujarat). In my birthh certificate my name like "Montu urfe Ankur". My father went to goverment office to change name from Montu to Ankur but at that time goverment employee wrote "Montu urfe Ankur". now i want to change my name and i need only "Ankurkumar" insted of "Montu urfe Ankur". 

please inform me what is procedure to change name in my b