public IHttpActionResult ReturnCar(int carID, int branchID) { if (!ModelState.IsValid) { return(BadRequest(ModelState)); } var out1 = new ObjectParameter("CarTableID", typeof(int)); var out2 = new ObjectParameter("RentID", typeof(int)); var res = db.spReturnCar(carID, out1, out2).ToList(); int?carTableID = out1.Value as int?; int?rentID = out2.Value as int?; if (rentID == null) { return(BadRequest()); } Car car = db.Cars.Find((int)carTableID); car.IsAvailable = true; car.BranchID = branchID; db.RentDetails.Find(rentID).ActualEndDate = DateTime.Now.Date; db.SaveChanges(); return(Ok(res)); }