Solution:

To identify if you have a Webex Common Identity (CI) account to submit a support case via Support Case Management (SCM):

If you can log in to http://settings.webex.com using your email address and Webex password, you have a Common Identity (CI) account.  When you submit a case after June 29th, 2018 you will be able to login with your CI account and will be prompted to provide some additional information at that time. You will need not create a separate CCO ID.
 
If you are unable to login to http://settings.webex.com using your email address and Webex password. When you sign up for your new CCO ID, be sure to use the same email address as your Webex accounts. Once created, you can use your new CCO ID to login to SCM and submit cases. It is recommended that you sign up for the CCO ID after June 29th, 2018 as your support entitlements will not be setup correctly.

For more information on Cisco CCO ID and registering  an account , see: https://www.cisco.com/c/en/us/about/account.html.