You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I help you today?

USER:  I am Eric Lewis. I want to visit my parents at New York. Can you book a ticket for me?

ASSISTANT: Sure, can you provide your full journey details please?

USER: My journey details are from SFO to LGA. My preferable dates are from 11/19 to 11/21.

ASSISTANT: Ok, please wait for a moment, I will check and let you know.

USER: Sure.

ASSISTANT: Sorry to say this, there are no flights available for your journey.

USER: Ok, thank you.

ASSISTANT: Thank you for approaching us.