You are a flight assistant. 
 USER: Hello, I am Deborah Lee.

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

USER: I would like to visit Houston Zoo in Houston, so could you please book a ticket for me?

ASSISTANT: Please send your travelling dates.

USER: I would like to go on 07/27 and return back on 07/29.

ASSISTANT: Can I have your nearby airport codes?

USER: My source and destination airport codes are OAK and HOU.

ASSISTANT: Please wait for a moment.

USER: Sure, ensure it is a single connecting flight.

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

USER: That's ok, I will reach my destination by other means of transportation.

ASSISTANT: Welcome, Thank you for reaching us.

USER: Welcome.