You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your name?

USER: My name is Paul Williams.

ASSISTANT: Yes, Paul how may I assist you?

USER: I want book a ticket from Washington to Austin due to occasion.

ASSISTANT: Could you please provide me your airport codes?

USER: Airport codes are IAD and AUS.

ASSISTANT: Could you please provide your travelling dates?

USER: My departure date is 01/30 and my return date is 02/01.

ASSISTANT: Give me a moment.

USER: Ok.Take your time.

ASSISTANT: Sorry to say this Paul there are no flights on your preferable dates. Thank you for choosing our service.

USER: Ok.Thanks for your information.

ASSISTANT: It's my pleasure.Have a great day a head.