You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Sarah Robinson here.

ASSISTANT: Sarah Robinson. How can I help you?

USER: Please book my ticket from PHL to AUS.

ASSISTANT: May I know the travel dates?

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

ASSISTANT: Is there any time concern?

USER: I want to return in the evening.

ASSISTANT: May I know the connection limit?

USER: I prefer economy class and I need a connecting flight.

ASSISTANT: Is there any class preference?

USER: I prefer economy class.

ASSISTANT: Any airline preferences?

USER: No.

ASSISTANT: Give me a minute.

USER: Sure.

ASSISTANT: Sorry to inform that there are no flights available on your route.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us.