When Creating an Event Invitation, you are simultaneously creating an Event Folder which contains the Event email and any Follow-up emails.
You can Delete a Follow-up Email if it's in draft.
If you'd like to delete the entire Event Folder (or the main event email), you'll need to follow steps to Delete the Folder.
Note: Only Event emails in Draft status can be deleted provided it is not the only email in a Folder. Live Emails that have been Approved and Sent cannot be deleted. Please contact Poppulo Support if you wish to delete a Live email.