You have to follow the guidelines for CBSE duplicate mark sheet

1.       Applicants should use separate form for each certificate. If necessary typed/Photostat  application form may be used.

2.       Candidate applying for duplicate documents and Migration Certificate upto Examination of 2001 may send application along with fee to the Deputy Secretary, Central Board of Secondary Education, Todarmal Marg, Ajmer, (Rajasthan). All payments be made in favour of Secretary, CBSE, payable at Ajmer and mode of payment shall be IPO / Bank Draft only. Those applying personally at Ajmer Office may deposit fee in cash also.

3.       Triplicate copy or of further copies of qualifying certificates shall not be issued unless the Controller of Examinations is further satisfied by some documentary evidence that the duplicate copy has also been actually lost / destroyed.

4.       In case the fee is remitted by crossed Postal Order / Bank Draft, it must be drawn in favour of the Secretary, Central Board of Secondary Education, payable at the concerned Regional Office.

5.       Fees prescribed for various certificates are as follows (DOCUMENTS WILL BE RECEIVED AFTER 15 DAYS ( EXCLUDING HOLIDAYS))

6  If certificate is required after two days (excluding holidays) an urgent fees of  Rs.500.00 extra may be remitted. If the certificate is required by post an extra amount of Rs. 25.00 may also be remitted. (Rs. 35/- for outstation candidates)

7         In case the document is not collected by the applicant within three months from the date of depositing the fees, it will be cancelled and the candidate will have to apply afresh in case he needs the same.

8.       The certificate will ordinarily be issued after two weeks (excluding holidays) from the date of receipt of the application from and the fee, provided the application form is found complete in all respects.

9.       Migration certificate is issued only to those candidates who have passed an examination of the Board or to those who have been placed in compartment in order to enable them to seek admission for a further course of study. The failed candidates should not apply for migration certificate and Provisional Certificate. Please also mention previous year's Roll No. if passed in second chance compartment examination for Provisional Certificate

10.   All certificates for Delhi Region will be delivered on the production of receipt issued by the Board between 3 to 5 PM only (excluding holidays). The fee from candidates of Delhi Region for 2003 and onwards examinations can be deposited between 9.15 AM to 1.15 PM on every working day at Syndicate Bank, PS 1-2, Institutional Area, Patparganj, Delhi-110092

11.   The students of Chennai Region who have passed examination in 1991 or later should apply to Chennai Regional office only for obtaining duplicate documents.

For the application form and other details refer

http://cbse.nic.in/newsite/dup.html