Once an item has been deleted from an account, it can be retrieved for 30 days thereafter.  To restore a previously deleted item from an account, click on the Deleted Items menu item.

Click in the checkbox to the right of the item that needs to be restored, and then click the Restore icon on the far right side of that item.  If there are multiple items that need to be restored, checkbox each item, and then click the Restore Selected Items button on the top right side of the screen.