Can I cancel a hotel booking myself in the system or do I have to email the supplier every time?

Yes, in most cases you can cancel a hotel booking yourself from the booking screen in your admin panel, without writing to anyone. When the supplier allows it, the cancel action goes straight through their API, the booking status changes to cancelled, and a cancellation reference comes back so you have proof. Your customer can be sent a cancellation confirmation from the same place, and the booking stays in your records with its new status rather than disappearing.

How much comes back to you depends entirely on the rate your customer booked and when you cancel. Every hotel rate carries its own deadline, and once that date has passed the booking is usually non refundable or only partly refundable. The system can show you the charge that will apply before you confirm the cancellation, but it does not set that charge, the supplier and the hotel do. For rates sold as non refundable from the start, cancelling will normally return nothing at all.

There are a few cases where it is not instant. Some suppliers only accept a cancellation request rather than an immediate cancellation, so the status will sit as requested until they reply. Bookings that were on request with the hotel in the first place often work this way too. And getting the money back to your customer is a separate step from cancelling with the supplier, because that depends on how you collected the payment and on your own payment provider's refund timings.

It is worth checking which of your connected suppliers support online cancellation and what their deadline rules are, so you know in advance which bookings you can handle yourself and which ones still need a message to their support team.