Plan and facilitate a retrospective

Running a retro that should produce change rather than a list of grumbles.

Design a retrospective for the situation below.

1. Choose a format suited to this specific situation and say why, rather than defaulting to went well / went badly.
2. Write the opening framing: two or three sentences that make it safe to be honest without sounding scripted.
3. Give the exact prompts I will put on screen, with timings for a session of the length I specify.
4. Include a step for surfacing things people are reluctant to say out loud, such as silent written input before discussion.
5. Describe how to get from a long list to at most three actions, each with an owner.
6. Give me two facilitation interventions: one for when the room blames a person, one for when it goes quiet.

Situation, team size and session length:

Before and during. Agendas, pre-reads, prep for a 1:1 or an exec slot, and plans for retros and workshops.