sir at the time of jee mains registration i had my ews certificate under procedure but now i got it pls tell how can i change my category or i can change it in april attempt ....and now i consider as ews in rank list or not.

Hello,
The date of correction is completed. So you can't do anything now. You will get your rank as per your details given in the application form.
In April term, you can apply for EWS at that time and use the documents when needed during counseling. You should have given in the application. This will happen again in April time also. So fill the application as per your details. You will get or make your documents later.
Hope it helps!