in jee correction form can i change mt category from general to ews ,as i dont have ews certificate now can i submit undertaking in correction form

Yes, you can make changes when the correction window opens for your session. Just make note of the certificate. It has to be in the format given in the nta guidelines. The correction window opens when the registration process for the corresponding session completes.

So keep a check on notifications.
For updates, you can use the link mentioned below.
https://engineering.careers360.com/exams/jee-main