Hi Mohan,
Please refer below,
Agent hotfix or upgrade are provided in AgentInstall.msi package. Using the installation command:
msiexec /i AgentInstall.msi /q INSTALLDIR="C:\Program Files\Manufacturer\Endpoint Agent\" ENDPOINTSERVER="hostname" SMC="smc.hostname" KEY="" SERVICENAME="EDPA" WATCHDOGNAME="WDP" ARPSYSTEMCOMPONENT="1" will return the error.
This command is included in the install_agent.bat provided with the package.
To solve this issue use the following commnad instead:
msiexec /i AgentInstall.msi /q REINSTALL=ALL REINSTALLMODE=vomus
NB: This command should ONLY be used for minor upgrades and patches.
This command is included in the upgrade_agent.bat file provided with 9.0.2 agent upgrade package
https://www-secure.symantec.com/connect/forums/dlp-upgrade