The auxiliary function Use reflection color is
selected on the contextual toolbar (the button is down). Disable
the function to draw the reflected geometry in true colors.
Select the stair.
Select Confirm. The Select Floors to Which Geometry Will
be Reflected list opens.
Select the option from the list [2nd aboveground floor] wall layout
Confirm by clicking OK. The program opens the 2nd floor plan
drawing-model pair.
You will be prompted: "Leave this drawing-model pair active?".
Select Yes.