You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I want to book a direct flight ticket to attend an emergency case at CA. Can you help me?

ASSISTANT: Sure, I can help you. Can I know your travel dates?

USER: June 12th and 14th are my travelling dates.

ASSISTANT: Noted. Please let me know your source and destination airport codes?

USER: CLT and SFO are my airport codes.

ASSISTANT: Noted. Can I know your specifications?

USER: I would like to travel in an economy class.

ASSISTANT: Noted. May I know your name?

USER: Michael Jackson.

ASSISTANT: Thank you. Please wait, let me check for the available flights.

USER: Ok.

ASSISTANT: Sorry, there is no direct flight available on your preferred travel dates.

USER: No issue. Thank you.

ASSISTANT: You are welcome.