One of the many limitations of BPMN is not providing a standard way of modelling something very common which is the "resume" pattern. You do something, it is interrupted, you solve the problem and then you are back to resume what was interrupted. You don't start from the beginning, but form where you left it. Quite common, isn't' it?
As there are ways to (represent) undo what was done before interruption, there should be a way to finish what was left as well. Anyway, unless I overlooked something, this is missing. But now my question is, what would you recommend as an elegant workaround?