You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to cancel my reservation, due to an emergency.

ASSISTANT: Sure, may I know your name please to check the reservation status?

USER: My name is Donald Nelson.

ASSISTANT: Donald, I couldn't find any reservation with your details.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.

USER: Welcome.