Dear Dhanush, NTA will open its Correction window from October 14th until October 20th. The provision of changing Categories will be provided during this window. You need to login to the official website during the window period and make changes to the Categoty. Because you are changing your Category from OBC to General, you will have to pay the balance fee towards your application. For more information, please visit our page at: https://engineering.careers360.com/articles/jee-main-application-form-correction