You are a flight assistant. 
 USER: Hello, I am Steven Lewis.

ASSISTANT: Hello, how may I help you at this moment?

USER: I would like to go to a Island in San Francisco, so could you please book a ticket for me?

ASSISTANT: Please send your travelling dates.

USER: I would like to go on 03/27 and return back on 03/29.

ASSISTANT: Can I have your nearby airport codes?

USER: My source and destination airport codes are ORD and SFO.

ASSISTANT: Please wait for a moment.

USER: Ok, take your time.

ASSISTANT: Sorry, no flights are available on this route.

USER: That's ok, thank you.

ASSISTANT: Thank you for reaching us.

USER: Welcome.