You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Could you book my ticket in a direct flight?

ASSISTANT: Sure, can you share me your travelling airport codes?

USER: My genesis and terminus airport codes are AUS and IAD.

ASSISTANT: Please mention your planning dates.

USER: My itinerary dates are July 23 and July 25.

ASSISTANT: Do you have any class preference?

USER: I have no other requirements.

ASSISTANT: Can I know your good name?

USER: Patrick Davis here.

ASSISTANT: Sorry, no flights are available in this route as per your requested dates.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us.