3.1.4.1 Flagging a Message Object
To flag a Message object, the client opens the object by sending a RopOpenMessage remote operation (ROP) request ([MS-OXCROPS] section 2.2.6.1). Message objects, other than Appointment objects, Journal objects, and Note objects, can be flagged.<13>
The client then sets properties on the object by using the property ROPs that are specified in [MS-OXCPRPT]. The properties that are set depend on the particular flag used, as specified in section 3.1.4.1.1 through section 3.1.4.1.6. In addition, some properties are not set on some Message objects. For details about property constraints, see the property definitions in section 2.2.1 through section 2.2.3.