Hello,
If you have entered your Aadhaar details in the JEE Main application as C. Sai but your updated Aadhaar shows Sai C., then you cannot change this directly unless the correction window is opened by NTA. After you reach the final stage before fee payment, most fields including Aadhaar details are locked and cannot be edited. You can submit the form as it is for now. When NTA opens the official correction window, you will be allowed to correct personal details such as name, Aadhaar number, or identity information. The name mismatch will not cancel your application, but you must carry the updated Aadhaar and any supporting document to the exam. If the correction window appears, make the correction immediately.