How to rename a subdomain?

I’m not sure how the question relates to WordPress? cPanel is used to manage your hosting. They also have their own forum where these questions are answered, here is a topic about it: https://support.cpanel.net/hc/en-us/community/posts/19137303221783-How-to-change-subdomain

If the question concerns WordPress, you also need to change the subdomain in WordPress. How to do this is described here: https://developer.wordpress.org/advanced-administration/upgrade/migrating/#changing-the-site-url