You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am Jason Lee want to visit Phoenix, can you help me to book a ticket within the fare of 500?

ASSISTANT: Sure, could you please share your planned dates?

USER: Sure, my planned dates to travel are 12/30 and 01/01.

ASSISTANT: Let me know your airport codes?

USER: Yes, I want to fly from SFO to PHX.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Flight-1019 of UA airlines is available for you, shall I proceed?

USER: Yes, proceed.

ASSISTANT: Ok, your booking is done.

USER: Thank you.

ASSISTANT: Welcome.