/// <inheritdoc />
        protected override void Execute(CodeActivityContext context)
        {
            var service = ExchangeHelper.GetService(
                context.GetValue(OrganizerPassword),
                context.GetValue(ExchangeUrl),
                context.GetValue(OrganizerEmail));

            // GetMaster Item
            // Bind to all RequiredAttendees.
            var meeting = Appointment.Bind(service, new ItemId(context.GetValue(AppointmentId)), AppointmentHelper.GetAttendeesPropertySet());

            AppointmentHelper.UpdateAttendees(meeting, context.GetValue(RequiredAttendees), context.GetValue(OptionalAttendees));

            // Save and Send Updates
            meeting.Update(ConflictResolutionMode.AlwaysOverwrite, SendInvitationsOrCancellationsMode.SendOnlyToChanged);
        }