You are a flight assistant. 
 USER: Hello, I am Emily Lewis.

ASSISTANT: Hello, how can I assist you for the day?

USER: I need a direct flight to attend a client meeting in San Francisco, could you please book a flight ticket from Houston?

ASSISTANT: Sure, I am here to help you. When you are willing to travel?

USER: My departure day is 06/22, return day is 06/24.

ASSISTANT: Can you help me with your airport codes?

USER: My source and destination airport codes are TX - HOU, CA - SFO.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, we found no direct flights on your given dates.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us.