You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I serve you?

USER: Can you please book a flight ticket from SEA to DEN?

ASSISTANT: Sure, please share your planned travel dates.

USER: I want to travel on dates Oct 20 and Oct 22.

ASSISTANT: May I know your connection limit?

USER: I need a direct flight.

ASSISTANT: Do you have any class preference?

USER: I want to return at afternoon.

ASSISTANT: May I know your name please?

USER: My name is Helen Williams.

ASSISTANT: Do you have any other preference?

USER: No.

ASSISTANT: We didn't find any flight which meets all your requirement.

USER: That's ok, thank you for the response.

ASSISTANT: Thank you for reaching us.