If you have entered a different Id type as in you wanted to enter your Aadhar details but entered PAN Card, it is still ok and for the exam hall you can still take Aadhar card and your verification process will be smooth. But if you have entered the Identification details wrong as in you entered the wrong Aadhar no#, you cannot make changes to it even during the correction window. You will have to re-register and fill a new application form all together.