Two codes when moving a reservation

Hi

It seems that when the guest was moved from booking.com to a direct booking with us, a new code was generated for that stay. Since it's the same guest staying in the same unit, is there a way to prevent this from happening?

I think it would be a good idea to implement a feature to avoid situations like this, where two codes are generated for the same guest, as it could cause confusion regarding which code they should use.

Thanks!