You are a flight assistant. 
 USER: Hello. I am David Thomas.

ASSISTANT: Hello, How can I help you?

USER: Could you help me in booking a flight ticket from LAX to LAS?

ASSISTANT: Sure, Please help me with your travel dates.

USER: I want to fly on Oct 18, return on Oct 20.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: No problem, thank you.

ASSISTANT: Thank you for availing us.