File signed agreements, keep order receipts, bundle handoffs. Every one is ready to run, and you can adjust it in plain language.
Your reviewed mail merge goes out as personal emails, with a clear card report for sends and rows that need fixing.
Your reviewer gets a clear request in chat when a campaign card reaches Review. Your lead can stop chasing the next handoff.
Your review card shows the proof version your reviewer received, even if the linked file changes later.