Global A as Integer

sub Line
    dim document   as object
    dim dispatcher as object
    document   = ThisComponent.CurrentController.Frame
    dispatcher = createUnoService("com.sun.star.frame.DispatchHelper")

    dim args2(1) as new com.sun.star.beans.PropertyValue
    args2(1).Name = "TopBottomMargin.BottomMargin"
    if A = 0 then     
        args2(1).Value = 200
        A = 1
    else
        args2(1).Value = 0
        A = 0
    end if
    dispatcher.executeDispatch(document, ".uno:TopBottomMargin", "", 0, args2())
end sub

Source: setting a keyboard shortcut for line space [closed] – Ask LibreOffice