Once a Promo Code is used in a Campaign (Active or Inactive) the only way to update it is to delete the Campaign and Enter the Code.
- The system won't allow you to update the Promo Code, considers it in use
- The system won't all you to duplicate the Campaign because the System will also say the Promo Code is already in Use.
- Not until the original Campaign with the Promo Code is deleted can a new Campaign be setup with the Promo Code.