Hello,

If you have not submitted the application and you have the option to change you can change. Or else if a specified time is avaialble for editing, you can change during that time. If you are out of all these options, you may contact the concerned authorities. Usually you give your e-mail id while registering and they instruct you that it cannot be edited.

And one solution that exist is that you may register using another email id if you or your close relatives have any such.