Hello,
You have yo tell us that for which entrance exam you are asking about.
But generally one can not edit his/her particulars after the correction dates are over.But in the worst case you have to contact to the concerned authorities through email or telephone numbers and tell them your problem.Then they might assist you better.
Good luck.

You can edit the details from application Correction window which appeared into the official website from first week of January 2018.

Please say which exam you are talking about and what mistake you have done in your application.

For which exam u have filled incorrect data. Try to contact with respective authority and tell your problem.

write an apology email to concerned authority.