Relaunch Campaign

Cancel a campaign pinned to a superseded playbook version and create its replacement on the approved current version -- one transaction (Stage E's "un-pause the honest way").

⛔GATED ON APPROVE, NOT WRITE, and for the same reason approving a campaign is: this decides who we are as a sender. A relaunch puts a different story in front of every account the old campaign held, and that is the same decision as approving the first one, arriving through a different door.