Hi,
It's possible to convert unmanged linux client to managed one.
After you install an unmanaged Symantec Endpoint Protection for Linux client, you can convert it to a managed client to centrally manage the client by importing the client-server communication settings file into the Linux client. A managed client communicates with and reports its status and other information to Symantec Endpoint Protection Manager.
This can be a reference guide to follow the steps: http://www.symantec.com/docs/HOWTO101768