You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Katherine Walker. I just want to cancel my reservation, due to some problem with my friend. Can you help me out?

ASSISTANT: Sure, wait for a minute.

USER: Ok.

ASSISTANT: Sorry, Walker  no reservation found on your name.

USER: Oh! that's fine.

ASSISTANT: Thank you for approaching us.

USER: Thank you for your help.