Hi,
Thank you for posting in Symantec community.
I would be glad to answer your query.
Now you can successfully replace communication file only with the help of Client Deployment Wizard (CDW). No need to re-deploy entire pacakge in case of communication issue.
SEP 12.1 RU2 onwards no need to use Sylink replacer utility.
You can check this article to learn more about it:
Restoring client-server communications by using a client installation package
http://www.symantec.com/docs/HOWTO80762
Forum article: https://www-secure.symantec.com/connect/articles/sep-12-ru2-and-reset-client-communication