Hello Naveen, Greetings!

Yes, you can change your caste from EWS to OBC in any exam's application form. But the method is, you can make the corrections during the 'correction period' mentioned by the authority. Exams like JEE, NEET have a 'correction period' of 7-8 days usually. Make sure to look when the correction period starts and make the changes accordingly. Please note, that the corrections made in this period will be considered as final and you won't be able to make any other corrections later on.

Hope this answer helps you.

Feel free to ask any more queries that trouble you.