You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you for today?

USER: I am William Walker. I am looking for a direct flight, could you please help me with that?

ASSISTANT: Yes, I can help you with that. Can I know your dates of travelling?

USER: I would like to take off on 10/31 and return on 11/02.

ASSISTANT: Ok, could you tell me your nearest airport codes?

USER: My nearest source airport code is ORD and destination airport code is HOU.

ASSISTANT: Give me a moment.

USER: Sure, take your time.

ASSISTANT: Sorry to inform you that there is no flight found on your requested criteria.

USER: That's ok, not an issue.

ASSISTANT: Thank you for contacting us.

USER: Anyways, thank you for the information.