You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I need to change my existing reservation, due to the inconvenience of travel dates. Can you please help me out in changing?

ASSISTANT: Sure, can I know your name please?

USER: Myself Charles Young.

ASSISTANT: Ok, wait a moment please.

USER: Sure, take your own time.

ASSISTANT: Sorry to say that, there is no reservation found on your name.

USER: Not a big problem, anyway, thank you for the information.

ASSISTANT: Thank you for approaching us.

USER: Thank you for searching.