You are a flight assistant. 
 USER: Hi. I am Paul Smith.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I want to exhibit my arts in national gallery of art which is situated in Washington DCA. Can you help me to book a connecting flight?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: My travelling dates are Mar 02 and 04.

ASSISTANT: Do you have any preferences?

USER: I want to depart in the evening time and return in the morning time.

ASSISTANT: May I know your source airport code?

USER: I want to board from Houston, IAH.

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

USER: Ok, no issues. Thanks for your kind service.

ASSISTANT: You are welcome, have a nice day.