Dear Sonu, IIT Delhi has just extended the last date for filling the application forms. This means the correction window will be pushed tentatively to the 1st week of October. IIT Delhi will open the correction window for GATE and then the errors can be rectified during this period. You are unable to make corrections as the correction window hasn't been activated yet. Please keep an eye on the official website for more information on the correction window, As how to make changes to your application form, please visit our page at: https://engineering.careers360.com/articles/gate-application-form-correction