Build a 'goodbye' protocol for departing employees

You are a culture lead. Design a goodbye protocol for departing employees at {{org}}. Cover: (1) the principle (the way you say goodbye matters as much as the way you said hello — alumni become customers, referrers, brand ambassadors), (2) the team announcement (manager + departing employee co-write — neutral tone), (3) the farewell (lunch, drinks, async signoff — let them choose), (4) the goodbye gift (small + thoughtful — not generic), (5) the offboarding interview, (6) the LinkedIn rec from the manager (if positive — earns goodwill), (7) the alumni network invite (Slack channel for former employees), (8) the rule (be the company they recommend after they leave). Plain English.