You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,. How can I help you?

USER: I want to book a flight ticket from TX-IAH to DC-DCA.

ASSISTANT: May I know your name please?

USER: I am Susan Hall.

ASSISTANT:  Sure, can you please provide your travelling dates ?

USER: My departure date is march 23 and return date is march 25.

ASSISTANT: OK, Please wait for a minute. I will check with your requirements and let you know. May I know if you have any connection and cost limit?

USER: My connection limit is 1 and price limit is 500.

ASSISTANT: Sorry, There is no flight as per your requirement.

USER: OK, thank you for your information.

ASSISTANT: Thank you. Have a nice day.