I am planning to use the split-domain setup for an exchange to zimbra migration, so that users who are not migrated, can still be mailed from migrated users. I am clear on the process to implement my Zimbra box, as the secondary server, but I am not clear on how to remove the forwarding action, after all migrations are completed, and the exchange server is removed. I don't want the Zimbra server to continue to push non-existing accounts into the abyss.