Hi Ed,
It should be there. I presume you are using V14 and the Pro version? It was not in V12 and I am not sure if it is available in Delux.
You must select the wall first, then right click. If you are using V12 then select the wall, hold shift and select all the other walls that are the same, one by one, so that they are all selected, then right click and choose Replace.
Allan