date to be confirmed

Suppose your telephone starts ringing.
You answer it.
Then a nice man says I'm xx (and you realize five minutes later it's your surgeon). He talks about a date that needs to be confirmed. You say yes.
Then, you check your calendar. You say no no no.
The man, a nice voice on the phone, says, ok.
and passes your long expected surgery to his next patient!

now, I need to call the other surgeon, and check his availability...