You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Please book a flight ticket from DFW to SFO to meet my family.

ASSISTANT: Sure, let me know your travelling dates?

USER: I have planned to travel Aug 07th and return on Aug 09th.

ASSISTANT: Do you have any connection limit?

USER: I prefer direct flight.

ASSISTANT: Is there any other preferences?

USER: No.

ASSISTANT: Can I know your name?

USER: Andrew Scott.

ASSISTANT: Thanks for your details, there is no flight found on your desired journey routes.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.