Hello Aspirant,

Corrections in the application form of UPSEE would be done via online mode. There is the one time opportunity for the candidates to correct mistakes in the filled-in application form. I'm not sure about it but you can try to upload your OBC certificate with correct norms in the second round for counselling of UPSEE.  You can contact with the helpline of UPSEE. For more Information I'm providing you a link that will help you:

https://engineering.careers360.com/articles/upsee-counselling

I hope this will help you.

All the best