The main, default layout cannot be removed, but you can remove any layout embedded within it. When a layout is removed, the portlets inside it are also removed from the page.
To remove an embedded layout, do the following:
Select My Folder in the navigation area.
Select the page you want to change. Then click the Edit icon
in the top
right corner of the page.Click the box in the upper left corner of the corresponding Page/Folder Customizer for the layout you want to remove.
To return to normal mode, click the View icon
in the top
right corner of the page.