Hello Manya,

If you have filled the application form in offline mode by taking form from the school or downloading via website, then you can take another copy of the application form, fill it and submit. If you have made a mistake on the application form in online mode, then contact the NTSE officials through mail explaining them your issue. They will tell you how to go about for the same. If they do not respond, then call them or else let it be. It wouldn't really cause a big issue. But, first try to contact and address them the issue.