You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Myself Ryan Walker. I want to travel with a direct flight to land at San Francisco as it is an urgent case, so please help me with booking a flight ticket.

ASSISTANT: Sure, I will help you to book a direct flight.

USER: Thank you.

ASSISTANT: May I know your source and destination airport codes?

USER: Yes, I will start from IAH and reach SFO.

ASSISTANT: Please mention your planned journey point?

USER: I have already mentioned above.

ASSISTANT: May I know your planned travelling dates?

USER: My preferable dates are 08/25 and 08/27.

ASSISTANT: Please share me your price limit?

USER: I can afford up to 500.

ASSISTANT: Thanks for the details, sorry there is no direct flight available on your journey details.

USER: No issues, thank you for the information.

ASSISTANT: Thank you for reaching us.