Dear aspirant hope you are doing well. Yes you can show you EWS certificate in your 2nd round counselling if and only if you filled your form in ews category in the application form. Simply the in counselling process, they who not have ews certificate, they have to fight with general candidate.. Also ews seats are only 10% . Ews seats are allotted to according to marks and income certificate..

Generally all seats for ews category get filled in 1 round counselling of top college / decent college.

Chance is less to get in ews seat in the decent college.

Thank you