You can change your cPanel password from the 'Hosting' -- 'My Hosting' area of your user account.
- Please log in to your user account
- Go to 'My Hosting Accounts' from your dashboard menu
- Click on the 2nd tool to the right of the domain name in question to bring up the 'Change Hosting Password' screen for that domain
- Enter and confirm the new password and click 'Save Changes' to finalize the change