If you wish to remove any email address you created for your domain name, that is possible to do. But please note that this process is irreversible and all the data will be lost.
To remove any email, you need to first open 'Email Accounts' from 'Email' section of your cPanel:
Once you open it, you can view all the email address that you've created for your domain name under 'Email Accounts' section of the page, something like this (please note email address in the screenshot has been hidden to avoid spam):
Simply click on delete button for the email you want to remove and confirm it by pressing on 'Remove' again:
Once you confirm it, your email address is removed from the system.