One thing that is not clear and it took me a long time to find.

Not everyone has the UNDO button available.

I am the company accountant and had to set myself up as if I were an outside accountant to get access to that button. That means no one else in the company can undo a reconciliation. That's good and bad. We don't want everyone changing a closed reconciliation, but it would be nice if permissions could be given from the Admin level.