You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Carolyn Lopez. I have postponed all my plans due to heavy traffic, can you please help me to change my existing reservation?

ASSISTANT: Give me a moment, let me check your details.

USER: Ok.

ASSISTANT: Sorry Lopez, I didn't find any reservation basing on your details.

USER: OK, no issue. Thank you for your information.

ASSISTANT: You are welcome.