parseRevokeSysPrivCommand =  OMBREVOKE ( SYS_PRIV | SYSTEM_PRIVILEGE ) 
          "sysPrivNameList" FROM ( USER "userOrRoleNameList" | ROLE 
          "userOrRoleNameList" ) 
     sysPrivNameList =  "UNQUOTED_STRING" { "," "UNQUOTED_STRING" }
     userOrRoleNameList =  "QUOTED_STRING" { "," "QUOTED_STRING" }
This clause revokes a list of system privileges from a list of users or roles.