You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: Can you please help me in booking from LGA to SFO?

ASSISTANT: Sure, can you share your trip dates?

USER: My trip dates are from Dec 14 to Dec 16.

ASSISTANT: Do you have any preferences?

USER: I want to return in the evening.

ASSISTANT: May I know your name?

USER: My name is Ruth Miller.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: Ok, No issues. Thank you.

ASSISTANT: Thank you for opting us.