You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Matthew Smith.

ASSISTANT: How can I aid you at this moment?

USER: I am planning to travel from DFW to SFO. Can you please help me to book a ticket?

ASSISTANT: Sure, I am here to help you. Could you please provide your journey dates?

USER: My journey starts on Mar 7 and return on Mar 9.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Do you have any connection limit for this trip?

USER: I need a connecting flight.

ASSISTANT: May I know your specific depart and arrival time?

USER: I want to depart in the evening.

ASSISTANT: Do you have any airline preference?

USER: No.

ASSISTANT: Matthew Smith, we regret to inform you that there are no flight services are available on this route with your preferences.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for contacting us.