I have a reservation from one guest, but need to cancel, because we have no more rooms available.

Direct the guest to their account on BdC website, or call CS team, else you need to call BdC PartnerSupport to assist.

Reminder you cannot post actions requests or any action request on here.

Message or Call BdC PartnerSupport ***

1. In the extranet, go to the ‘Inbox’ tab.
2. Select ‘Booking.com messages’.
3. Right Pane - Click on ‘See Contact Options’. 
4. Choose Account
5. Now choose Other
6. Then at bottom , See all contact options, and click Message or Call
7. As there is no one number for all partners, the number for your nearest BdC Partner Support is then revealed.

*** public main lines via Where you can reach us