3.1.4.6 Updating E-Mail Flags on the Server

A client SHOULD add a flag to an e-mail message, mark a flag on an e-mail message as complete, or clear a flag from an e-mail message by sending a Sync command request ([MS-ASCMD] section 2.2.1.21) to the server, as specified in sections 3.1.5.4 and 3.1.5.4.1.