How to delete Facebook event
To delete the event you have created on Facebook just go to Facebook event page and open your event.
Click this link to go to your events page:
On your events page open the event you would like to delete, for example click “My Birthday” if you have created the event with this title.
On your event dashboard, click on EDIT (pencil icon) as shown below.
Then the last step is to click the “Cancel Event” which will appear in your edit event box.
Then your Facebook event will be deleted.