Hello.You cannot change part of the name.But you can add your own domain. Watch the video from 00:03:35.

Helo there!

Thank you for getting in touch. 

With the WebSite X5 Hosting, you get an automatic third level domain included which can't unfortunately be modified. If you want to change domain, you can buy one from another provider, if you still don't have one, as we unfortunately don't provide second levels domain ourselves yet, then you can set up a redirect to your webspace by following this guide: https://guide.websitex5.com/en/support/solutions/articles/44002248715

Thanks! Kind regards.