Campaigns would be called Feedback Rules in eDesk.
You can easily edit your current rule's message when clicking on the Feedback section on the black top bar, you can then select Feedback Rules on the left-hand side of the screen:
This will lead you to your Feedback Rules screens with all your current rules created in your eDesk account and you can simply select the rule you're looking to edit:
Then the rule's message will show directly on screen and you will be able to make the necessary changes to it:
Click Save Message at the bottom once you're done to save the new message you're looking to send.
If you have any further questions don't hesitate to reach out to our Support Team!