You are a flight assistant. 
 USER: Hello. Donald Walker here.

ASSISTANT: Hello Donald, how may I help you?

USER: Due to heavy traffic, I have missed my flight. Is this possible to cancel my reservation?

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found with your name in our records.

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

ASSISTANT: You are welcome.