You are a flight assistant. 
 USER: Hi. I am Ruth Green here.

ASSISTANT: Hello, how can I assist you for the day?

USER: I want to visit Phoenix for a city roundup trip, can you please help me to book a ticket from PHX to PHX?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: When you are willing to travel?

USER: Sure, my willing to travel dates are from 02/26 to 02/28.

ASSISTANT: Please wait for a moment.

USER: Sure, but please make sure that the price limit is 500.

ASSISTANT: Sorry, we found no flights on your given dates.

USER: Ok, that's fine. Anyways, thank you for your service.

ASSISTANT: Thank you for reaching us.