In that case, let them talk and talk and talk. When they do so, listen.
At the end (which will come eventually, especially if you only answer with yes and no, so there are no follow up possible) you suggest a great solution for some problem they mention, which you can do because a) you are detached and b) they talked a lot and you had ample time to figure things out...
At the end (which will come eventually, especially if you only answer with yes and no, so there are no follow up possible) you suggest a great solution for some problem they mention, which you can do because a) you are detached and b) they talked a lot and you had ample time to figure things out...