Let’s say you had an action to “Phone: Bob about TPS report.” If you phoned Bob and left a message, you’ll likely want to create a new action to reflect that you’re waiting for a response.
This plug-in automatically marks the action complete and creates a duplicate “waiting” action. With a minor addition (documented on the plug-in page), this plug-in can also apply the tag of your choice to the duplicate action. Consider assigning a keyboard shortcut to this plug-in to make it even quicker and more convenient.