To edit a creative in Campaign Manager, find it in your campaign or advertiser. Click the creative to open its properties and make changes.
Keep in mind that multiple campaigns in your advertiser may use the same creative, so your changes may affect more than one campaign. Your edits take effect everywhere. If you change the creative name, its name will change in every campaign. If you deactivate the creative, it will be inactive in every campaign.
Different creative types have different properties. Check the Type in your creative properties to be sure which kind you're editing.
Here are links to instructions to create, set up, and edit each creative type: