Mr. Mohan
Your old ICSI account wont let you change your information so First You need to transfer your profile by clicking on this site https://smash.icsi.in/scripts/login.aspx
Just follow simple steps
1. click on above link
2. Enter your ID
3 Click Forgot password
4.Generate new password
and then login into your new SMASH account from there you can change your email Id and whatever you wanted to change.