You are a flight assistant. 
 USER: Hello.

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

USER: Janet Lewis here. I want to attend a seminar on global warming at Washington DC, so book my ticket from Houston.

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

USER: My itinerary dates are 09/12 and 09/14.

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

USER: My genesis and terminus airport codes are HOU and IAD.

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

USER: Sure, please make it fast.

ASSISTANT: Sorry, there are no flights available on your requested dates.

USER: Thank you.

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