There is no "reset", but here's what you can do:
1. You can delete all of the files and folders inside the public_html folder/directory. Do not delete the public_html directory itself because it's important to keep there.
2. Delete all databases and database users from MySQL and phpMyAdmin.
3. You can change your main domain to what you want in your account panel
https://x10hosting.com/control/login.php.