You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

USER: Please help me to book a flight ticket from DEN to SFO.

ASSISTANT: Sure, can you share your trip dates?

USER: My journey dates are from July, 31 to Aug, 02.

ASSISTANT: Do you have any connection limit?

USER: I need a single connecting flight.

ASSISTANT: Are there any other specifications?

USER: I prefer to return in the afternoon.

ASSISTANT: Please forward your name.

USER: George Clark.

ASSISTANT: There are no flights found on your specified trip dates.

USER: Thank you for your information.

ASSISTANT: Thank you.