noun
waiting for a cancellation; being on a waiting list
Commonly used for reservations, tickets, appointments, or any limited-availability service where you wait for someone else to cancel.
満席だったので、キャンセル待ちを申し込んだ。
Since it was fully booked, I put myself on the waiting list for cancellations.
キャンセル待ちでやっと予約が取れた。
I finally got a reservation after waiting for a cancellation.