The first ten seconds
Drop your voice half a step. Turn your body 45 degrees off-line — full square-on is confrontational. Palms open at waist height. Eye contact steady, not staring.
The script that works
'I can see this is really frustrating. Help me understand what happened so I can sort it out.' Emotion acknowledged first, problem-solving second.
The off-ramp
'Here's what I can do right now. If that doesn't work for you, we can escalate to the duty manager.' You've given the person a face-saving choice.
When de-escalation fails
You have a pre-decided trigger — usually the moment weapons, threats to specific people, or attempted physical contact appear. At that trigger, escalation to police is instant.