Thanks for your reply.
But I am not able to send meeting from delegate user. I am using the following code to send.
ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2010);
service.Credentials = new NetworkCredential("adminusername", "password");
service.UseDefaultCredentials = false;
service.AutodiscoverUrl("admin@test.com", RedirectionUrlValidationCallback);
DelegateUser newDelegate = new DelegateUser("delegate@test.com");
newDelegate.Permissions.CalendarFolderPermissionLevel = DelegateFolderPermissionLevel.Editor;
List<DelegateUser> delegatesToAdd = new List<DelegateUser>();
delegatesToAdd.Add(newDelegate);
Mailbox mailbox = new Mailbox("admin@test.com");
Collection<DelegateUserResponse> result = service.AddDelegates(mailbox, MeetingRequestsDeliveryScope.DelegatesAndSendInformationToMe, delegatesToAdd);
Appointment appointment = new Appointment(service);
appointment.Subject = "Status Meeting";
appointment.Body = "The purpose of this meeting is to discuss status.";
appointment.Start = new DateTime(2015, 8, 6, 10, 40, 0);
appointment.End = appointment.Start.AddMinutes(15);
appointment.Location = "Conf Room";
appointment.RequiredAttendees.Add("attendee@test.com");
//appointment.Save(SendInvitationsMode.SendToAllAndSaveCopy);
appointment.Save(new FolderId(WellKnownFolderName.Calendar, "admin@test.com"), SendInvitationsMode.SendToAllAndSaveCopy);
The above code is sending mail from ADMIN not from DELEGATE.Please suggest how can I send it from delegate.