Greetings !!

Yes, You can. At the time of correction time, you may change the wrong entered details , but make sure that for all the corrections made you have valid documents to prove the authenticity of the details entered. In the language change there won't be any issue. But you can't be bilingual in any exam. You need to follow either Hindi or English. if any doubts, pls feel free to ask.

Wish You Good Luck !

Thank You !!