You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I would like to meet my friend at Chicago, can you please help me to book my flight ticket from SFO to ORD?

ASSISTANT: Can I know your travelling dates?

USER: Sure, I will depart on Nov 28th and return back on Nov 30th.

ASSISTANT: Do you have any preference?

USER: Yes, please check for the flight with single connection.

ASSISTANT: Let me know your name.

USER: My name is Charles Edwards.

ASSISTANT: Sorry, no flight found for your travelling dates.

USER: No problem, thank you for checking.

ASSISTANT: Thank you.