You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: I want to travel AUS from DCA, can you help me to book flight ticket with this?

ASSISTANT: Sure, can you please share me with your dates of journey?

USER: My travelling dates are July 19 and July 21.

ASSISTANT: May I know your name please?

USER: David Clark here.

ASSISTANT: Do you need any other help from my side?

USER: I prefer direct flight to travel.

ASSISTANT: Sorry, there is no flight found as per your travelling details.

USER: Ok, not a problem. Thank you.

ASSISTANT: You are welcome.