Flags are case sensitiv:

/S	Silent mode
/D=PATH	Target directory. Default is used, if parameter missing.
/MANAGEDRECORDING=1		Only Primary VRM (uninstalls Secondary)
/MANAGEDRECORDING=2		Only Secodary VRM (uninstalls Primary)
/MANAGEDRECORDING=3		Both /Primary and Secodary
/RCPP1=xxxx		RCPP port for Primary VRM 
/RCPP2=yyyyy	RCPP port for Secondary VRM 
/HTTP1=vvvv		HTTP port for Primary VRM 
/HTTP2=zzzz		HTTP port for Secondary VRM
/HTTPS1=uuuu	HTTPS port for Primary VRM
/HTTPS2=wwww	HTTPS port for Secondary VRM

The Setup_VRMServer_Setup.exe does not support complete uninstallation.
To uninstall VRM (both instances) the Uninstall.exe from the installation folder must be used.