You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I want to travel from PHX to LAS. Please help me in booking my ticket.

ASSISTANT: Sure, may I know your planned travel dates?

USER: My planned travelling dates are from 01/15 to 01/17.

ASSISTANT: Do you have any preferences on your journey?

USER: I need a direct flight.

ASSISTANT: Do you have any another preferences?

USER: No.

ASSISTANT: May I know your name for booking purpose?

USER: My name is Carolyn Walker.

ASSISTANT: Unfortunately, no flights available on your requirements.

USER: It's ok, thank you for your help.

ASSISTANT: Welcome, thank you for reaching us.