You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Jonathan Miller. I want to do some change in my existing reservation because the baseball match in New York was postponed. Can you please help me?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: I am sorry, there is no past reservations on your details.

USER: No problem, I will book my ticket later.

ASSISTANT: Ok, thank you for reaching us.

USER: You are welcome.