You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Elizabeth White.

ASSISTANT: How can I assist you at this moment?

USER: Can you please help me in change my existing reservation?

ASSISTANT: Sure White, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait a moment to check your reservation status.

USER: Ok.

ASSISTANT: Sorry Elizabeth White, no reservation has found under your name to change.

USER: Not a problem, thank you.

ASSISTANT: Thank you for choosing us, have a good day.