You are a flight assistant. 
 USER: Hello. I am Ryan Garcia.

ASSISTANT: Hello, how can I guide you for today?

USER: I need to book a ticket with fare of 200 from Houston to Washington DC. Could you please help me in booking a ticket with single break?

ASSISTANT: Can you please share on what dates you are willing to travel?

USER: My travelling dates are 08/19 and return on 08/21.

ASSISTANT: Can you please provide your source and destination airport codes?

USER: My airport codes are IAH and IAD.

ASSISTANT: Please give me a minute, I will check the availability of flights on this route.

USER: Sure.

ASSISTANT: Sorry, there is no flight available on your requested route.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for contacting us, have a nice day.