You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I help you?

USER: I want to fly to Charlotte on Sept 27th to attend my sister's engagement, could you please help me to book a flight ticket?

ASSISTANT: Sure, May I know your airport codes?

USER: My boarding and landing airport codes are IAH and CLT.

ASSISTANT: When are you willing to coming back?

USER: I want to return from NC on Sep 29th in the afternoon time.

ASSISTANT: Let me know your connection limit.

USER: I prefer to fly with the connecting flight for this time.

ASSISTANT: Are there any other preferences?

USER: No more specifications for this time.

ASSISTANT: May I know your name?

USER: I am Karen Baker.

ASSISTANT: Sorry to say that, there are no flights found on your data.

USER: That's ok, I'll choose any alternative to reach my destination. Thank you for your information.

ASSISTANT: Ok, Thank you.