You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I am Margaret Campbell. Can you please book a flight ticket from DCA to AUS?

ASSISTANT: Sure, I am gleeful to help you. Could you please provide your travelling dates to search for the flight?

USER: Sure, I need to travel on dates of 03/17 and 03/19.

ASSISTANT: Just hold on a moment, I will check flight availability in this route.

USER: Sure, take your time to check.

ASSISTANT: Sorry to say, no flights were available on your route.

USER: Oh! It is sad to hear. Anyway, I will choose another agency this time. Thank you for your time.

ASSISTANT: Thank you for reaching us, have a nice day.