The message can't be moved, but you can create a new message in the correct campaign and copy the HTML content over to the new message in the correct campaign.

How to access the email message and copy the HTML code:
  1. Click Email > Email Campaigns.
  2. Click the Campaigns tab. A list of email campaigns displays.
  3. Click Manage in the Actions column of the incorrect email campaign. The campaign summary tab displays.
  4. Click the Messages tab. A list of the messages for the campaign displays.
  5. Click Edit in the Actions column for the appropriate message.
  6. Go to step 4, and click HTML Content
  7. Copy the message's HTML code
  8. Navigate to the correct email campaign by repeating steps 1-6, and replace the HTML code with the copied code
  9. Click Save
    • Note: You would want to click Send Review Email in step 6 of the email message to send a test email and confirm that the email content is correct
  10. Go to step 7, and click Approve