You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I am Barbara Garcia. I am planning to book a ticket form DFW to DEN. Can you please help me out?

ASSISTANT: Sure, May I know your travelling dates?

USER: I am planning to travel on May 25 and return back on May 27.

ASSISTANT: Do you have any connection limit?

USER: I am looking for a connecting flight.

ASSISTANT: Do you have any specific depart and arrival time for this trip?

USER: My return time should be evening.

ASSISTANT: Is there any other preferences?

USER: I am looking for a economy class.

ASSISTANT: Thanks for your details, there are no flights found on your data.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you.