The validity of EWS certificate is 1 Financial year and so your EWS certificate would have expired by April 2020. Now it is no more valid. And so you cannot upload that certificate now. You will need to upload a renewed EWS certificate. And State NEET registration applications do not have correction windows. Once you submit the application form, you cannot make any changes further. So you cannot upload an expired EWS certificate now and then reuplaod a valid and renewed EWS certificate. You have to upload a new one.