On each of the layouts from which the user may choose to go to this layout, use a script to save the layout's name in a global variable. The OnLayoutExit trigger is one choice for this script, but you might also use navigation buttons that save the layout name and then change to this layout.
Set Variable [ $$PrevLayout ; value: Get ( LayoutName ) ]
Then to return to this previous layout, use:
Go to Layout [ $$PrevLayout ]
and select the "Layout Name by Calculation" option for this go to layout script step.
O.K. Thanks Phil,
Is completely clear. I thought there might perhaps be an expression for this. But the "Set Variable" works just fine.