You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am William Thompson.

ASSISTANT: How can I assist you?

USER: Actually, there is a small change in my holiday trip.

ASSISTANT: OK.

USER: Can you help me out in changing my reservation?

ASSISTANT: Sure, I would Happy to help you? Jest give me a minute?

USER: Sure.

ASSISTANT: Sorry to say that there is no reservation found.

USER: Oh! that's fine. Thank you for your help.

ASSISTANT: Thank you.