You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I serve you?

USER: I am Justin Wilson. I want to change my existing reservation as my friends comic con is postponed. Can you help me out?

ASSISTANT: Sure. Please wait for a while. Thanks for waiting, there is no reservation found on your name.

USER: Ok. Thank you for your information.

ASSISTANT: Thank you have a nice day.