You can only edit promotions that are active or haven't started yet. To do so, follow these steps:Go to your Facebook page and click on the "Publishing Tools" tab in the top menu.In the left-hand menu, click on the "Promotions" tab.Find the promotion you want to edit and click on the "Edit" button.Make any necessary changes to the budget, target market, or duration.Review your changes and click "Save" to update your promotion.