if you mean the datbase of the site:
Head over to phpMyAdmin. In cPanel, you can access it through the Databases section of the home page. Once there, select your database from the menu on the left, then click the Operations tab at the top. You can rename your database to whatever you would like as long as you only include letters and numbers.
If you mean the credentials from wp-config.php, that exists in the root dir.
