You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to book a flight ticket from PHL to LAS. Can you find a flight ticket for me?

ASSISTANT: Please provide your journey dates?

USER: Ok, my planned trip dates are on Oct 29 and return on Oct 31.

ASSISTANT: Do you have any preference?

USER: Ok, I need a single connecting flight.

ASSISTANT: Can I know your name?

USER: Ok, my name is Mary Walker.

ASSISTANT: I regret, there is no flight for your travelling dates.

USER: Ok, not a problem.

ASSISTANT: Thank you.

USER: Thank you for your information.