You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Shirley Robinson, want to travel from BOS to SFO. Can you please help me?

ASSISTANT: Sure, may I know your travel dates please?

USER: My travel dates are from 07/21 to 07/23.

ASSISTANT: May I know your connection limit?

USER: My connection limit is 1.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Do you have any airline preference?

USER: No, thanks.

ASSISTANT: Let me know your depart and arrival timings.

USER: My return time is evening.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there are no flights running on your desired routes.

USER: It's ok, thank you.

ASSISTANT: Thank you for visiting us.