You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Janet Jackson here.

ASSISTANT: How can I assist you?

USER: I want to change my existing reservation due to heavy snowfall in JFK.

ASSISTANT: Sure, give me a minute.

USER: Sure.

ASSISTANT: I will help you that. I am sorry to say that there is no reservation found.

USER: That's fine, thanks for your information.

ASSISTANT: Thank you for contacting us.