Keerthana, NTA has reopened the correction window until July 20th. You had a chance to make corrections to your Category during this period. But if you have missed that opportunity, you cannot make any changes to the application form any further. This is important because NTA has clearly mentioned intis Information Brochure that it will not entertain any requests for changes in Category nor will it change the details on its own once the correction window has been closed. So if you were not able to make any changes to your Category from General Category to EWS during the correction window, you cannot appear for Counselling and admission using your EWS Category certificate  because the merit list is prepared on the basis of the Category you have selected during the time of filling the NEET application form. Now it is too late. You have to appear for Counselling and admission process as a Candidate belonging to General Category only. Unfortunately, changing to EWS Category is not possible at this point in time.