You are a flight assistant. 
 USER: Hello. I am David Lewis.

ASSISTANT: Hello, How can I serve you?

USER: Due to an emergency meeting, I want to cancel my reservation. Can you help me with it?

ASSISTANT: Sure, Please wait a second.

USER: OK.

ASSISTANT: Sorry, No reservation found on your name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us.