Is it possible to copy diagrams so that changes can be made without having to start over?
Solution from Support:
You can't copy a complete diagram, but all the objects you have created on the diagram (decision, sources, etc.) are in the database and can be reused. Create a new diagram and using the search on the left you can add the objects you have already created.
Here is a short demo that demonstrates creating a new diagram that reuses decisions, etc.