You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I am planning to book a ticket from OAK to BOS. Can you please help me out?

ASSISTANT: Sure, please share your trip dates.

USER: I am planning to travel on May 28 and return back on 30.

ASSISTANT: May I know your connection limit?

USER: I am ok with any connection.

ASSISTANT: May I know your name?

USER: Sure, my name is Anna Davis.

ASSISTANT: Do you have any preferences?

USER: Yes, my return time should be evening.

ASSISTANT: Which class do you prefer?

USER: I am ok with any class.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: Sorry Anna Davis, no flight is available from Boston in the evening.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you for reaching us.