You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Can you help me to book a flight ticket from DEN to DFW?

ASSISTANT: Sure, may I know the travelling dates?

USER: I will start on Sept, 21 and return on Sept, 23.

ASSISTANT: Please help me with your connection limit.

USER: I would prefer single connection.

ASSISTANT: Do you have any other requirements?

USER: No.

ASSISTANT: May I know your name?

USER: Nancy Carter here.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, no flights found with your preferable dates.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for availing us.