You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you for the day?

USER: Please book me a flight ticket from SFO to ORD to meet my family.

ASSISTANT: When you are willing to travel?

USER: I have planned to travel on May 15th and return on May 17th.

ASSISTANT: May, I know your good name?

USER: Catherine Smith.

ASSISTANT: Do you have any connection limit?

USER: I prefer connecting flight.

ASSISTANT: Do you have other specifications?

USER: I want to depart at evening time.

ASSISTANT: Sorry. we flights no flights on your given dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.