Tools - Marking Cells - Redefine Selected Cells

Ribbon bar. Select the Tools tab. Click Marked Cells and from the menu, select Redefine Selected Cells...

Classic menus. From the Tools - Marking Cells submenu, select Redefine Selected Cells (or click the toolbar button located on the Tools toolbar)...

...to replace the current set of marked cells with the selected cells in the spreadsheet (i.e., the Marked Cells spreadsheet layout will be applied to the selected cells AND removed from all unselected cells in the spreadsheet). See also: Format - Overview, Spreadsheet Layouts - Overview.