Regarding the cancellation process of Booking reservations through, the user can start the routine in only two cases:

The card provided by guests is invalidIt is possible to signal through Stays to the Booking team that the guest card has not been validated.
With this, the guest will have a deadline to insert another card or the reservation will be canceled by Booking.
Guests did not show up (no-show)24 hours after the arrival of the guest, you will be able to initiate the cancellation of the reservation through Stays, however it is necessary that you mark the [Mark reservation as "no-show" in the extranet] little box.SEE DETAILS
Remember that in reservation cancellation routines on Booking, the channel policies prevail in the negotiation with guests, so it is essential to link your Stays cancellation policies with those on Booking!
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In addition to the cases presented in the table above, it is important to mention that if the reservation is canceled by the guest through the Booking portal, Stays receives this information and will automatically delete the reservation in your calendar, so it is important that you set it to receive email notifications about reservation changes.

Now that you know about the Booking and Stays cancellation routine, it is worth reviewing the Booking policies on cancellations or reviewing other settings in your Stays channel manager in the connection with Booking.