You can easily remove a subdomain using the cPanel interface. To get started, follow the directions below.
1. Login to cPanel.
2. When the page loads, click on the "Subdomains" link in the Domains section.
3. When the page loads, find the subdomain you want remove and click on the "Remove" link.
4. The next page will state the following confirmation:
"Are you sure you wish to permanently remove the support.cpx3demo.com subdomain?"
5. Click the "Yes" button if you want to permanently delete the subdomain. If you click on the "No" button, you will be returned to the subdomains list page. Or you can click on the "Go Back" to return to the previous page. Continue below if you are choosing to delete the subdomain permentanly by clicking on the "Yes" button.
6. The next page will state the following confirmation:
"The subdomain support.cpx3demo.com has been successfully removed."