An element can be assigned to only one layer.
Select the elements whose layer you want to change.
In SmartSketch: On the Main toolbar, click Layers .
In Catalog Manager: Click Tools > Layers.
On the Layer ribbon, click Change Layer.
On the Change Layer dialog box, in the Change all to list, click the layer to change the elements to.
You can also change the layer of an element by selecting the element and clicking Properties on the Edit menu.