You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help today?

USER: Can you please change my existing reservation?

ASSISTANT: Sure, I am here to help you with that. May I know your name?

USER: I am Jeffrey Taylor.

ASSISTANT: Ok, wait for a minute.

USER: Sure.

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

USER: It's ok, thank you.

ASSISTANT: Thank you for reaching us.