When to use it
Use it at the end of any update, presentation or long comment. A one-sentence summary plus the one thing you need from people gives the room something to remember and act on. Prepare that closing line before the meeting so you don't trail off.
Example
You: “To sum up: we launch Tuesday, and I need your sign-off by Friday.”
Director: “Got it. I'll review Thursday.”
In an email or Slack message
In email, put the summary at the top instead of the bottom: “Summary: launch Tuesday. Need: your sign-off by Friday.” Then add details below for anyone who wants them.