Cannot suppress system reboot when uninstall a msi package

I am trying to install/uninstall a msi package from command line by using
msiexec.

The msi package is generated by InstallShield program from 3rd party merge
modules.

I have no problem install the package. However, I cannot seem to suppress
the reboot duirng the uninstallation.

There is the command I use for uninstallation:

Msiexec /uninstall C:\64bitMsi.msi /qn REBOOT=ReallySuppress

Thank you very much,

REBOOT=R ought to suppress any reboots instigated by the intrinsic
ForceReboot or ScheduleReboot actions that occur during the install.
However if your install contains any custom actions that trigger a
reboot they will not be covered by this. What is the return code from
your call to msiexec.exe? And what do you see in the log - you will
need to switch logging on by adding the /l*v c:\temp\msilog.txt or
somesuch to your command line.