You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I would like to change my reservation, could you help me out?

ASSISTANT: Sure, may I know your good name please? Ok, please wait for a moment.

USER: Sure, take your time. My name is Jack Walker.

ASSISTANT: Sorry, there is no reservation found on your name in our database to change.

USER: That's ok. Thank you for your time.

ASSISTANT: Thank you for approaching us.