1. Create a segment by clicking the add rule bar and selecting "Message Engagement."
2. From the dropdown next to "Pass if contact," choose "Received a message."
3. Select the name of the incomplete broadcast you want to resume.
4. Save and exit the segment setup.
5. Duplicate the incomplete broadcast by clicking "Duplicate" in the Actions menu.
6. On the broadcast recipients page, add the segment you created to the "Suppression and Exclusion" section.
7. Click "Calculate Suppression" to verify that the contact count is correct—this prevents recipients who have already received the broadcast from getting a duplicate email.