To edit a mailing list, click either link besides the mailing list in the Mailing Lists widget, or click the button when viewing the mailing list.
You will then be prompted to make your changes. Click to save your changes. The mailing list will automatically synchronise after you have made any changes (there may be a delay in this occurring).
If you are using Campaign Monitor, you cannot change your API key or Client ID settings once they are set. If you need to, you must delete this mailing list then creating a new mailing list.