Name Change

My name is Ramendra Singh. I wanna change my name to Rohan Singh. I live in Khurja, Dist - Bulandshahr, UP. Pin - 203131. I completed my 12th std from CBSE in 2015. After taking a drop year in between I was admitted to an engineering course (B.E.) in PUSSGRC, Hoshiarpur , Punjab , affiliated to Panjab University, Chandigarh. Currently I am in 4th semester. Is it easier for me to change my name within the degree or should I go for it after completion of the course. Tell me in details about the procedure to be followed in both the cases and suggest the best one. Will the name change in all the documents including 10th, 12th mark sheet etc still require in the second case or just the affidavit would be enough.