API notifications

The default scrip action is setup to point to channel general:

  @ScripActions = (
        {
            Name        => 'Notify Slack',
            Description => 'Post ticket updates to slack channel',
            ExecModule  => 'NotifySlack',
            Argument    => '#general',
        },
   );

You can create a new action or update the existing one ( I don’t recall offhand 100% if you can modify an existing action created by code ) to point to your new slack channel.

If you’re on RT 4.4.4 and up you should be able to go to Admin->Global->Actions in the web UI