Click on Tracking Tags on the menu bar. Click on Delete beside the tracking tag to be deleted.
When you click on Delete (Step 2), you will be asked to confirm your choice. Click the Confirm Delete button to confirm that you want to permanently remove this tracking tag.
Note that when a tracking tag has been deleted, it can no longer be used in campaign filtering.
When the tracking tag has been deleted, you will be returned to the Tracking Tags screen.