If a Team Member tries to delete a Segment from your Instance that is currently being used in a Blast’s Target Audience, they will be stopped from performing this action.
This ensures that your Blasts do not lose part of their Target Audience, or their entire Target Audience, before they are meant to be sent.
If you try to delete a Segment that is currently being used in a Blast's Target Audience, you will see the following message:
"Delete Not Allowed. You can't delete [Segment name} because it's being used by the following Blasts:"
After this message, you will see a list of the scheduled and drafted Blasts that are currently Targeting that Segment inside their Audience.
If you would still like to delete this Segment, you will first need to delete the Segment from the Target Audience of all the Blasts in the pop-up modal list. After you delete the Segment from the Blast(s), you can go back into Audience > Segments and delete the Segment from your Instance.