You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Gregory Thompson.

ASSISTANT: How best I can respond to your request?

USER: I need to book a flight ticket to attend a business conference meeting at PHX, Can you please help me for booking from SFO?

ASSISTANT: Sure, may I know your travel dates?

USER: I would like to travel on 11/21 to 11/23.

ASSISTANT: At what price range are you looking for?

USER: I can pay up to 5000.

ASSISTANT: Sorry Gregory Thompson, there is no flight on your route.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you.