public static void ConfirmRequest(Consultation request) { if (request != null) { Console.WriteLine("Write duration of consulteation(by minutes)."); bool t = false; int duration = 0; while (!t) { try { duration = Convert.ToInt32(Console.ReadLine()); t = true; } catch (FormatException) { MessageBox.Show("Write duration of consulteation by minutes."); } } Consultation newConsultation = new Consultation(request.StartOfConsultation, request.StartOfConsultation.AddMinutes(duration), request.Patient); Doctor myDoctor = (Doctor)myUser; myDoctor.ServeAPatient(newConsultation); myDoctor.ListOfRequests.Remove(request); } }