You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I help you?

USER: Please help me to book a flight ticket from SFO to AUS.

ASSISTANT: Sure, May I know your travelling dates?

USER: My journey dates are from Mar, 18 to Mar, 20.

ASSISTANT: Do you have any connection limit?

USER: I need a single connecting flight.

ASSISTANT: Any other preferences?

USER: I prefer to return in the evening.

ASSISTANT: May I know your name?

USER: Karen Thomas.

ASSISTANT: Sorry, there are no flights found with your details.

USER: Thank you for your information.

ASSISTANT: Thank you.