Hello @Cecilia884 and welcome to ABB CC from across the lands and seas in Auckland, New Zealand
Rather than do an outright cancellation, how about offering an 'Alteration" to the dates that you both currently have an agreement for so you can both look forward to meeting each other and sharing an experience at a future date?
That way it's win-win for you both.
Have a browse here in CC using related keywords to learn how others in similar situations have handled such a situation and reach out to your Guests to offer an alternative then neither party loses monies or has the hassle of worrying about refunds.
You can both keep in touch with each other via the message system with updates and if necessary change the Alternative dates should the need arise.
All the best
Central To All Home & Location, Auckland, NZ