The move comes after it was found that candidates have committed mistakes while filling particulars in their online registration form, CBSE said in a statement today.
However, no corrections can be carried for changes in examination cities and option for change of mode of examination from computer-based examination (online) to pen- and-paper based examination, it said.
The online registration form has been made available on JEE Main website from November 8 December 15.
As per the new format, aspirants for IIT will have to appear for JEE Main and then for JEE Advance.