If you've checked the Receive Approval Notifications on the Preferences page, you'll receive an email every time an ad or ad edit requires approval. If not, you can go to Zone Mgmt->Ad Spaces Pending Approval->Edit Status. Once on this Edit Status page, you can update the Approval Status. You can also disable this ad space or even make this ad space free.
You can also click Edit Space to edit any element of this ad.
