Hi,
Remote push is one of the available option but auto upgrade is more easy to use.
http://www.symantec.com/docs/HOWTO17911
To modify installed features for managed clients
- In Symantec Endpoint Protection Manager (SEPM), click Admin.
- Click Install Packages on the bottom.
- Click Client Install Feature Set on the top.
- If a feature set that meets the required needs does not exist, then choose Add Client Install Feature Set.
- Give the feature set a unique name.
- Select the features needed (Antivirus/Antispyware, Network Threat Protection, Proactive Threat Protection).
- Choose OK.
- On the left, click Clients.
- Select the group with the SEP clients in it, and then click the Install Packages tab in the right pane.
- Under Tasks, choose Add Client Install Package.
- In that screen, select the correct package in the drop down menu for use with this group (32 bit or 64 bit base install files). Both packages can be separately assigned to the same group.
- Uncheck Maintain existing client features when updating.
- Below that, select the feature set needed from the dropdown menu.
- If Upgrade Schedule is not selected, then clients will receive the instructions to change their installation when they check in with the manager. This launches MSIEXEC on the client.
- After the installation completes, a restart is required if the change installs or uninstalls Network Threat Protection.
Reference: http://www.symantec.com/docs/TECH90936