public string UpdateInstructorInfo(Instructor instructor) { var errors = new List <string>(); var repository = new InstructorRepository(); var service = new InstructorService(repository); service.UpdateInstructorInfo(new Instructor() { Id = instructor.Id, FirstName = instructor.FirstName, LastName = instructor.LastName }, ref errors); if (errors.Count == 0) { return("ok"); } return("error"); }