You have two options for taking pages out of the website: archiving and deleting.
Note you cannot delete a menu node if it has pages associated with it. You must first move the pages or delete them.
You can only delete pages from Menus & Pages, not from Site Editor.
To delete a page:
Note: When you delete a page, you only delete the instance of the page. The page's content items remain stored in the iAPPS database for later reuse.
You cannot delete content from the Data Libraries, only archive it.
You can archive a page that has previously been published to make it no longer visible on a site.
You can only archive pages that have been published. Otherwise, delete the draft page instead.