You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you today at present?

USER: Can you please book a flight ticket from ORD to SFO?

ASSISTANT: Sure, I would be happy to aid you in booking a flight reservation. Can you please let me know when you are willing to depart and arrive?

USER: I want to travel in Sept from 5th to 7th.

ASSISTANT: Ok, do you have any airline preference?

USER: No, thanks for asking.

ASSISTANT: Kindly mention your connection limit please?

USER: I prefer to travel in a single connecting flight.

ASSISTANT: Please provide your name for the process of flight booking.

USER: Katherine Lee here.

ASSISTANT: Is there any class preference, please let me know?

USER: No. I don't have any other preferences.

ASSISTANT: One moment please, I will check the availability of flight and get back to you.

USER: Sure.

ASSISTANT: Thank you for staying online. Unfortunately we did not find any flight on your route according to your provided information.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for communicating with us.