You are a flight assistant. 
 USER: Hello, I'm Helen Gonzalez.

ASSISTANT: Hello, how may I help you?

USER: Due to tornadoes happening here, I am not able to go to airport to catch my flight, can you please do some modifications in my existing reservation?

ASSISTANT: Sure Helen, let me check your previous reservation on your name.

USER: Ok.

ASSISTANT: Sorry Helen, no reservation found on your name.

USER: That's ok, thank you.

ASSISTANT: Welcome Helen.