You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Dennis Lewis.

ASSISTANT: How can I assist you today?

USER: Can you help me booking a flight ticket from PHX to OAK?

ASSISTANT: Sure, can you please share your travel dates?

USER: I will start on Feb, 09 and return on Feb, 11.

ASSISTANT: Do you have any class preference?

USER: I am comfortable with any class.

ASSISTANT: Dennis Lewis, there is no flight available at your requested dates.

USER: No problem, thank you for reaching us.

ASSISTANT: You are welcome. Thank you for reaching us.