You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Donald Hill.

ASSISTANT: How can I help you today?

USER: Can you please help me to book a flight ticket form Boston to Denver?

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

USER: My travelling dates are Dec 6 to Dec 8.

ASSISTANT: Ok, may I know your travelling airport codes?

USER: My airport codes are BOS to DEN.

ASSISTANT: Let me know your departure time and arrival time.

USER: I want to return in the evening.

ASSISTANT: Do you have any connection limit?

USER: I need a flight with single connection.

ASSISTANT: sorry, no flights are available on your preferable travel dates.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for checking.