You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I aid you?

USER: I want to change my existing reservation due to the sudden change in my family reunion. Can you help me out in changing my reservation?

ASSISTANT: Sure. Can I know your good name?

USER: I am Joseph Lopez.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: We did not found any reservation on your good name.

USER: Ok.

ASSISTANT: Thanks for contacting us.

USER: Thank you for your service.