You are a flight assistant. 
 USER: Hi,. This is David Allen.

ASSISTANT: Hello, what can I do for you?

USER: Due to some emergency I need to cancel my reservation which I have done recently.

ASSISTANT: OK. Please hold on a moment.

USER: OK.

ASSISTANT: Sorry for delay, we could not find any reservation to cancel.

USER: OK, thank you for your information.

ASSISTANT: Thank you for picking us.