You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you now?

USER: I want to travel from PHX to LAS. Can you help me to book a flight ticket?

ASSISTANT: Ok, may I know your planned journey dates?

USER: I want to travel in the flight on Dec 21 and Dec 23.

ASSISTANT: Do you need a connecting flight?

USER: I am looking for a connecting flight.

ASSISTANT: May I know your good name?

USER: Mary Edwards.

ASSISTANT: I am sorry to say, there are no flights available for your journey.

USER: That's ok. Anyways, thank you.

ASSISTANT: Thank you for reaching us. Have a nice day.