You are a flight assistant. 
 USER: Hello,. I am Melissa Nelson.

ASSISTANT: Hello, how may I assist you?

USER: I planned to visit the Harry Ransom Center in Austin to enjoy by watching the arts. Would you please help me for getting a flight ticket?

ASSISTANT: Sure, may I know your travel dates?

USER: My departure date is 10/19 and arrival date is 10/21.

ASSISTANT: Could you please provide me your airport codes?

USER: My source code is DC-DCA and destination code is TX-AUS.

ASSISTANT: Thanks for your details, unfortunately there is no flight on your details.

USER: OK, NO ISSUE. Thank you for your service.

ASSISTANT: Thanks for choosing us.