You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Katherine King.

ASSISTANT: How may I help you?

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Ok, wait a moment please.

USER: Sure.

ASSISTANT: Thanks for your time, there is no reservation found on your name to change it.

USER: Ok, no problem.

ASSISTANT: Thanks for choosing us, have a nice day.

USER: Thank you for your time.