For example, let's say you have the first and second floor 95% finished and the customer asks to add an elevator which makes you have to redesign the staircase and entry on both floors. You have it edited on the first floor and it's a neat little package that can just be duplicated line for line on the second floor but it's got curves, angles etc. that means it's going to be a bear to trace.
What is the best way to get that assembly installed on the second floor drawing with the least amount of time spent?