You want to schedule the installation of the Symantec Management Agent.
IT Management Suite (ITMS) 8.x
This method is available for Windows computers only.
A scheduled Symantec Management Agent installation is performed at a defined time, unlike the manual push installations which are performed immediately. You can push the Symantec Management Agent to the computers in an organizational group, filter, or resource target, or the computers that have selected resources.
Note that the agents that you install with scheduled push do not bypass the agent registration process.
To configure the Symantec Management Agent for Windows installation schedule
In the Symantec Management Console, on the Actions menu, click Agents/Plug-ins > Push Symantec Management Agent.
On the Symantec Management Agent Install page, under Scheduled Push to Computers, at the right of the page, click the colored circle, and then click On.
Under Apply To, specify the computers on which the Symantec Management Agent is to be installed.
You can specify an existing organizational group, filter, or resource target. You can also select individual resources.
Under When to Schedule panel, specify the scheduled time or schedule window to perform the installation and select the appropriate options.
Click Save changes.
Source: Performing a scheduled installation of the Symantec Management Agent for Windows
Note:
This method only installs the Symantec Management Agent (Altiris Agent) on the targeted machine(s). Any other Solution plug-in installation requires that you enable the related Installation policy.