You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: I am Mark Harris want to attend my brother-in-law's marriage at Houston, can you book a ticket with price under 200?

ASSISTANT: Sure, I will help you with that. Can I have your travelling dates please.

USER: Sure, my travelling dates are 02/01 and 02/03.

ASSISTANT: Sure, may I know your exact airport codes?

USER: Yes, I want to fly from JFK to IAH.

ASSISTANT: Ok, one moment  please.

USER: Ok.

ASSISTANT: Sorry to inform you that, their are no flight's available on your travelling dates.

USER: That's fine, thank you.

ASSISTANT: Thank you for contacting us. Have a nice day.