Clarify the agreement that existed
Identify the promise, policy, schedule, ownership, or shared understanding that applies before assigning blame. For a message about how to invite a former colleague to a work event, use this factual base: give the event, date, location, relevant history, and what kind of contact the invitation involves.
Resolve the next dependency
State what is complete, what remains disputed, and which action would move the situation forward. Offer a simple way to accept, decline, ask a practical question, or choose a lower-contact option. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Document without threatening
Do not announce their attendance, use relatives to persuade them, or make a public gesture before they agree. Respect no-contact, venue safety, custody, and legal restrictions even when the event feels important. Keep a factual record and describe only remedies you are entitled and prepared to use.