Often when you are talking to someone trying to persuade them to do something, you are going to have subjects meandering all over the place and you need to keep track.  What is helpful is simply say, “Let me interrupt you for a moment and tell you what I think I understand so far.”  If you do that, you keep the relationship on track, the conversation makes sense, and you summarized what you understood in components.  When you do that, the person actually is relieved, because you are managing the conversation.  So a component close is dividing up the conversation into bits by saying “let me tell you what I think I understand so far and see if I’m right.”  When you do that the person is going to feel relieved and you are going to stay on track.