You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: Myself Justin Miller. I want to change my existing reservation, can you help me?

ASSISTANT: Sure, I am here to help you. Please wait a moment I will check your complete reservation details and proceed further.

USER: Ok, take your time.

ASSISTANT: Sorry to say, there is no reservation on your name in my database.

USER: Ok, not a problem thank you.

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