If you want to remove one of your pages from the list of registered pages, simply tap the trash icon from the page you want to remove.
After pressing the trash icon, the page is automatically removed from the list.
This action only removes page temporarily.
This means that if you update your sitemap, the removed page if it is included in your sitemap, will also be added to the registered pages list again. The same applies if you manually add it with the add to page button.