You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I aid you today?

USER: I am William Harris. Me and my friends were planning to go for a shopping in national mall which is in Phoenix. Could you please help me for booking a flight ticket?

ASSISTANT: Sure, when do you like to travel?

USER: I like to travel on 10/14. I intend to return on 10/16.

ASSISTANT: Ok, please help me with your airport codes?

USER: My airport codes are CA-LAX and AZ-PHX.

ASSISTANT: Ok, any other requirements?

USER: I need a direct flight. Price should be under 500.

ASSISTANT: Ok, please wait I will get back to you.

USER: Sure.

ASSISTANT: Thanks for waiting,. Unfortunately no flights found with your requested details.

USER: Thank you for your good service.

ASSISTANT: Thanks for communicating with us.