You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation. Could you help me with that?

ASSISTANT: Sure, I can help you. May I know your name to check your ticket status in our database?

USER: Betty Collins here.

ASSISTANT: Please wait for a moment Betty Collins.

USER: Ok.

ASSISTANT: Sorry, no reservation is available by your name.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.