Hi Ajeevan,
Thank you for the post.
You cannot change your id(username) within our website. But for sure, we can help you change your ID.
Could you please send us email at 
 and let us know which ID you want to change?
Then our customer service team would be taking care of the issue.
Please use the email that you used for sing-up the account.
Thank you.
Sincerely,
Jay Lee