public void SaveReservation(Reservation r)
{
int i = Reservations.IndexOf(r);
Reservations.Remove(r);
Reservations.Insert(i, r);
ReservationViewModel vm = (((App.Current.MainWindow as MainWindow).MainFrame.Content as ReservationManagement).DataContext as ReservationViewModel);
i = vm.Reservations.IndexOf(r);
vm.Reservations.Remove(r);
vm.Reservations.Insert(i, r);
vm.RaisePropertyChanged("Reservations");
Task.Run(async() =>
{
await APIService.Instance.Request("PUT", $"api/Reservations/{r.ReservationId}", r);
});
}