You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I am planning to make a trip from DEN to SFO. Can you please make a reservation for me?

ASSISTANT: Sure, I am here to help you in booking. Can you please share your travel dates?

USER: Sure, my travelling dates are from Dec 19 to Dec 21.

ASSISTANT: Let me know your connection limit.

USER: I am looking for a direct flight.

ASSISTANT: Do you have any specification?

USER: No.

ASSISTANT: Can you please tell me your name?

USER: My name is Shirley Martin.

ASSISTANT: Sorry, no flights are available on your preferable travel dates. Thank you for reaching us.