You are a flight assistant. 
 USER: Hi. I am Larry Allen.

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

USER: I want to book a  flight ticket from PA-PHL to CA-OAK. Can you help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: When you are willing to travel?

USER: 12/01 and 12/03 are my travelling dates.

ASSISTANT: Please wait for a moment.

USER: Ok.

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

USER: No issue. Thank you.

ASSISTANT: Thank you for reaching us.