To edit a Campaign, from the "Manage Campaigns" tab, click the "Actions" button under the Campaign you would like to edit, and click "Edit Campaign."  From here you will be able to rename the Campaign and edit your Geo-targeting settings.   Remember, Campaigns can only show Ads on one search engine, so if you want this same Campaign to run on both search engines, you'll need to create a similar Campaign for the second search engine.  From the Actions button, you can also Pause, Delete or Activate the Campaign.