@Stephanie41 You need to inform yourself of what happens if a host cancels a reservation. Your calendar will be blocked for those dates so you can't rebook it (no, you can't unblock them), you will have "Host cancelled this reservation" on your review page, which makes prospective guests wary of booking with you, and you will be fined. If you have Superhost status, you will lose it for even 1 cancellation.
If a guest wants to cancel, you tell them to cancel from their end. The only time a host should cancel is if the cancellation is due to something on the hosts' end, and that would usually fall under the "extenuating circumstances" policy, like your plumbing sprung a leak, your water heater died, you have a medical emergency, etc., making it impossible to host until things are fixed. And in that case, you'd contact Airbnb to cancel for you, you don't do it yourself.