Problem with SendOnlyToChanged

Hi

I tried to use EWS API 2.0 to remove an attendee from the exchange calendar meeting with option "SendOnlyToChanged". Removed attendee received an email with "cancel" the meeting but others attendees also received an email with update the meeting. I don't know why because I set SendOnlyToChanged option.

So every time when I removed attendee others received an meeting update.

My code:

ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2010_SP2);
service.Credentials = CredentialCache.DefaultNetworkCredentials;
service.ImpersonatedUserId = new ImpersonatedUserId(ConnectingIdType.SmtpAddress,email@email);
service.AutodiscoverUrl("email@email");

String sEntryID = _szkolenie_item["outlook_calendar_item_id"].ToString();
String sEWSID = GetConvertedEWSID(service, sEntryID, "email@email");

Appointment _spotkanie = Appointment.Bind(service, new ItemId(sEWSID));
                                            
for (int i = 0; i < _spotkanie.RequiredAttendees.Count; i++)
{
if (_spotkanie.RequiredAttendees[i].Address.ToLower().Equals(getSPUser(_site2, _zapisy_item["uczestnik"].ToString()).Email.ToLower()))
{
_spotkanie.RequiredAttendees.RemoveAt(i);
break;
}
}
_spotkanie.Update(ConflictResolutionMode.AlwaysOverwrite, SendInvitationsOrCancellationsMode.SendOnlyToChanged);

 Anybody can explain why this happened and how to fix it ?

MNiemczycki