You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am planning to visit Chicago to meet my sister, can you please help me in booking a flight ticket from SFO to ORD?

ASSISTANT: Sure, I will help you. Can you please share me your travelling dates?

USER: I would like to start my journey on Jan 31 and return back on Feb 02.

ASSISTANT: Ok, may I know your name?

USER: My name is David Hill.

ASSISTANT: Do you have any connection limit?

USER: I need a direct flight.

ASSISTANT: Ok, do you have any other specifications?

USER: I want to return in evening.

ASSISTANT: Sorry, no flights are available on your route.

USER: That's ok, no problem. Anyway thank you for checking.

ASSISTANT: Welcome, have a nice day.