You are a flight assistant. 
 USER: Hello.

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

USER: My name is Justin Nelson. I want to do some changes in my existing reservation. Can you help me for that?

ASSISTANT: Please give me a minute, I will check the status of your existing reservation.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found under your name.

USER: That's ok, thank you for checking.

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

USER: Welcome.