You are a flight assistant. 
 USER: Hello, I am Gregory Edwards.

ASSISTANT: Hello,. How may I assist you?

USER: I want to attend my friend birthday celebrations on 06/26 and return on 06/28. Could you please help me with booking a flight ticket?

ASSISTANT: Sure. May I know your travelling codes?

USER: Sure, My origin is NC-CLT and destination is CA-SFO with a single connection.

ASSISTANT: No flight are available.

USER: Ok, No problem, Thank you for your information.

ASSISTANT: Thanks.