Approval workflow gives outreach managers an opportunity to directly oversee the activity of their team. When this feature is enabled, the head of an outreach team has the ability to accept or reject opportunities sitting in the 'Compose' stage of the workflow. Rejected opportunities will be sent back to 'Personalize'.
To learn how to turn on Approval Workflow, see Campaign Settings: General
When rejecting an opportunity, the outreach manager is given the option to leave notes detailing the reasons for rejection. Team members can view these notes next time they log in and personalize the opportunity again with improvements.