First you should swear an affidavit before a Notary and get it attested by him. Give a public notice in popular news paper one English & one vernacular notifying the change of name. Submit copies of these to your employer together with amended Aadhaar, PAN, Ration cards, Voter ID, get them verified by HR. Request them to make the changes in service records, nominations as well. Side by side, using these documents get the amendment in Bank a/cs, passport, DL, rent agreement, employee ID as well.