You have to file writ petition in Delhi HC to direct CBSE to change your name in school leaving certificate to charming Biswas

2) enclose your birth certificate which reflects your full name

Bye-laws 69.1 and 69.2 of the CBSE Bye-laws. . There is a bar/prohibition and a time limit has been fixed in the bye-laws. Bye-law 69.2 which deals with the change or correction of date of birth, reads as under:-

"69.2 Change/correction in Date of Birth i. No change in the date of birth once recorded in the Board's records shall be made. However, corrections to correct typographical and other errors to make certificate consistent with the school records can be made provided that corrections in the school records should not have been made after the submission of application form for admission to Examination to the Board.

ii. Such correction in Date of Birth of a candidate in case of genuine clerical errors will be made under orders of the Chairman where it is established to the satisfaction of the Chairman that the wrong entry was made erroneously in the list of candidates/application form of the candidate for the examination.

iii. Request for correction in Date of Birth shall be forwarded by the Head of the School along with attested Photostat copies of :

(a) Application for admission of the candidate to the School;

(b) Portion of the page of admission and withdrawal register where entry of date of birth has been made along with attested copy of Certificate issued by the Municipal Authority, if available, as proof of Date of Birth submitted at the time of seeking admission; and

(c) The school leaving Certificate of the previous school submitted at the time of admission.

iv. The application for correction in date of birth duly forwarded by the Head of school along with documents mentioned in Byelaws 69.2(iii) shall be entertained by the Board only within two years of the date of declaration of result of Class X Examination. No correction whatsoever shall be made on application submitted after the said period of two years."

in view of said provisions in bye laws your only remedy is to file writ in HC to direct CBSE to reflect your full name in school leaving certificate

You can make an affidavit stating that the name in the birth certificate and the name found in the CBSE certificate are one and the same and both belongs to you.

This affidavit may be notarized and also a newspaper publication may be given to this effect.

Keep both the affidavit an the newspaper copy along with your educational certificate and the birth certificate to produce it before authorities when ever it becomes necessary for any transaction or business.