public HttpResponseMessage Put(string id, Traveler traveler) { // returning 404 if the entity doesn't exist if (travelers.FindBy(t => t.TravelerUserIdentity == id).FirstOrDefault() == null) { return(Request.CreateResponse(HttpStatusCode.NotFound)); } if (traveler.TravelerId == 0) { return(Request.CreateResponse(HttpStatusCode.BadRequest)); } travelers.Edit(traveler); travelers.Save(); return(Request.CreateResponse(HttpStatusCode.OK)); }