You can put that machine to a new group in SEPM which has automatic liveupdate enabled with a schedule
If you want to make it as unmanged then you need to import the Sylink from CD1 ( SEP) folder
To convert the Symantec Endpoint Protection clients to unmanaged after they have been installed as managed
1.Locate the Sylink.xml file that is located on the installation media in the SEP folder.
2.Copy the Sylink.xml file to a location that is accessible to clients on the network.
3.In the install media, navigate to \TOOLS\NOSUPPORT\SYLINKDROP.
Run SylinkDrop.exe on each Symantec Endpoint Protection client that needs to be converted to an unmanaged client. Additionally in SEP 12.1, you can import the Sylink.xml file from within the client interface by clicking Help, then Troubleshooting, then clicking on Import under Communication Settings.
4.To prevent the client from switching back to managed, ensure that the sylink.bak file on the SEP client is deleted