You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I guide you for today?

USER: Kathleen Roberts here. Can you change my existing reservation?

ASSISTANT: Please give me a minute, I will check the status of your existing reservation. Sorry, there is no reservation found under your name.

USER: Sure. It's ok, thanks for checking.

ASSISTANT: Thank you for contacting us, have a nice day.