Dear @Catherine-Powell ,
I thought I would post my experience with a guest cancellation as many seem to write about poor experiences here.
Our guest cancelled as his daughter has been selected to play for her country and hence wouldn't be attending a local tennis tournament. The date was about 5 weeks in advance so they were refunded 50%, our calendar was opened up, and our payout set to 50% of the original payout minus the cleaning fee.
The guest asked nicely if we would refund the rest.
The website options available were to send money to the guest but this wouldn't have got the guest their service fees back.
A quick call to Airbnb Customer Services (1 min wait) got everything sorted such that the cancellation changed from 'guest' to 'Airbnb' and the guest was refunded in full with no impact to me (other than the service chap making it clear we would be paid nothing).
All in all a simple process that could only have been bettered if I could have done it all online.