You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Virginia Clark here.

ASSISTANT: How can I assist you?

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

ASSISTANT: Sure Virginia, please wait a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: That's ok, thank you.

ASSISTANT: You are welcome.