You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Karen Edwards.

ASSISTANT: How can I aid you Karen?

USER: Can you change my existing reservation?

ASSISTANT: Sure, please wait for a while.

USER: Sure.

ASSISTANT: Sorry Karen, I did not find any reservation under your name.

USER: Ok, not an issue. Thank you.

ASSISTANT: You are welcome, have a nice day.