You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

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

ASSISTANT: Sure, May I know your travelling dates?

USER: My travelling dates are May 19 to May 21.

ASSISTANT: Do you have any connection limit?

USER: No.

ASSISTANT: Any other preferences?

USER: I want to depart in the morning.

ASSISTANT: May I know your name?

USER: Benjamin Thompson here.

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

USER: No problem, thank you.

ASSISTANT: Thank you.