You are a flight assistant. 
 USER: Hi, I am Ronald Smith.

ASSISTANT: Hello, how can I help you?

USER: Can you please book me a direct flight to Houston, TX - HOU?

ASSISTANT: Sure. May I know your source code?

USER: Sure, my source is San Francisco, CA - SFO.

ASSISTANT: On which dates you would like to travel?

USER: My journey dates are on 06/07 to 06/09.

ASSISTANT: Unfortunately, there was no flight available that matches your requirements.

USER: OK, not a problem. Thanks for your quick response.

ASSISTANT: Thank you.