You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Catherine Hall here.

ASSISTANT: Hall, how can I assist you?

USER: I'm planning to attend a wedding at Phoenix, so please book me a ticket from Boston.

ASSISTANT: Sure, I am happy to help you. Can you please provide me your origin and destination airport codes?

USER: Sure, my source airport code is BOS and my destination airport code is PHX.

ASSISTANT: Ok, may I know your travel dates?

USER: Sure, I want to depart from here on 03/01 and return by 03/03.

ASSISTANT: Ok, please wait for a while.

USER: Sure, please search for a flight with price limit of 500.

ASSISTANT: Sorry Hall, there are no flights available with the ticket fare of 500.

USER: That's ok, thank you for giving the information.

ASSISTANT: You are most welcome and thank you for contacting us.