I want to change my full name in all certificate is it possible? can someone help me personally?

hello i am from jharkhand, dist- bokaro. i want to change my full name in all certificate (Metric,Inter,Graduation). Full name means at present my name is "Rahul sharma" and now i want to change into new name "Rajat Kumar" is it possible in jharkhand state? i have done my graduation from Vinoba bhave Univesrsity Hazaribag.please tell me step by step what is the proceeds what do i do. If someone want to help me personally then mail me - rajeshkr39@yahoo.in i will pay your fees thank you so much. as soon as after mail we will be meet personally thanks