You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to attend a steampunk festival with my colleagues at Washington, so could you please aid me with booking a flight ticket from Houston, TX-HOU?

ASSISTANT: Sure, may I know the exact code of Washington?

USER: Washington airport code is DC-DCA.

ASSISTANT: OK, on what dates you have planned for your journey?

USER: I have planned to fly out on 12/25 and return on 12/27.

ASSISTANT: Do you want a connecting flight?

USER: Yes, I want a connecting flight.

ASSISTANT: Can I have your name please?

USER: My name is Angela Lewis.

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

USER: Not a problem, I will try with another airline.

ASSISTANT: Thank you for choosing our service.

USER: Thank you.