public static Task ModifyRole(this ConferenceSession session,
                               ConversationParticipant participant,
                               ConferencingRole role, ModifyRoleOptions options)
 {
     return(Task.Factory.FromAsync(session.BeginModifyRole,
                                   session.EndModifyRole, participant, role, options, null));
 }
        //public static Task ModifyConferenceConfigurationAsync(this ConferenceSession session,
        //    ConferenceAccessLevel accessLevel, LobbyBypass lobbyBypass, 
        //    AutomaticLeaderAssignment automaticLeaderAssignment,
        //    ModifyConferenceConfigurationOptions options)
        //{
        //    return Task.Factory.FromAsync(session.BeginModifyConferenceConfiguration,
        //        session.EndModifyConferenceConfiguration, accessLevel, lobbyBypass,
        //        automaticLeaderAssignment, options, null);
        //}

        public static Task ModifyRole(this ConferenceSession session,
            ConversationParticipant participant,
            ConferencingRole role)
        {
            return Task.Factory.FromAsync(session.BeginModifyRole, 
                session.EndModifyRole, participant, role, null);
        }