Marcus,
You can do that. You’ll need to install and activate the WP Editor plugin to access the file you need to change. Once you’ve activated it, go to the Appearance section and select the Theme Editor there.
In the right, you’ll see the files in your theme. Choose the “includes” folder and then the “post-types” folder in it. Then choose staff.php there. Look for this line:
'menu_icon' => get_template_directory_uri() . '/images/staff.png',
Right above that paste this:
'rewrite' => array( 'slug' => 'team' ),
where team is the word you’d like to have in your URL’s. Save your changes.
Then go to the Settings section and select Permalinks. Click update at the bottom of the screen. Wait for the page to refresh and then click update again.
That should update your URL’s for you.
If you have any trouble, let me know,
Bill