A cancelled Opera reservations that has been reinstated by a hotel is unfortunately not something that the Impala API is currently able to handle.
The reason for this is that Impala checks if a booking has been cancelled by looking at the cancelled date. When a reservation is reinstated within Opera, the PMS does not remove the cancelled date and as a result of Impala still sees the reservation as cancelled and therefore the booking status is not updated.
We do realize that as a result of the uncertainties brought about COVID-19 sometime cancelled reservations can be reactivated. If this is something that you have encountered then we would recommend that instead of reinstating those reservations that the hotel create new bookings.