You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Can you please cancel my reservation due to my bad health, I can't make it?

ASSISTANT: Ok, may I know your name?

USER: I am David Allen.

ASSISTANT: Please allow me to check with availability of your booking.

USER: Sure, take your time.

ASSISTANT: David Allen, there is no reservation by your name.

USER: That's ok, thank you for your help.

ASSISTANT: Thank you for choosing us.