public JsonResult SaveReservationInstructions(SaveReservationInstructions command)
        {
            if (command.Id == null || command.Id.Equals(Guid.Empty))
            {
                return(Json(command));
            }

            Domain.Dispatcher.SendCommand(command);
            return(Json(command));
        }
        public IEnumerable Handle(Func <Guid, ContingentAggregate> al, SaveReservationInstructions command)
        {
            var contingentAggregate = al(command.Id);

            yield return(new ReservationInstructionsChanged
            {
                Id = command.Id,
                Instructions = command.Instructions,
            });
        }