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 one year of the date of declaration of result. No correction whatsoever shall be made on application submitted after the said period of one year.
Application Form: http://cbse.nic.in/faq/dob_mod_form_2015.pdf
If opportunity doesn't knock, build a door. - Milton Berle