Select the wall surface containing the cornice, and navigate to the Wall Section properties panel on the left.

Select the Wall Cornice dropdown menu, and select the cornice profile you wish to edit from the dropdown menu

Select Edit Active Profile

In the Edit mode, select the entire shape, and select Move icon in the toolbar

Click on the base point of the shape, move your mouse in the desired direction and type in the desired distance value by which you want to shift cornice

Select Apply to save changes