You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Mark Phillips.

ASSISTANT: How may I assist you Mark?

USER: I am planning to attend the convocation meeting at Phoenix, can you please help me with booking a flight ticket?

ASSISTANT: Sure, I will help you. Provide your desired travel dates please?

USER: Sure, I would like to take off on 05/24 and return back on 05/26.

ASSISTANT: Please share your airport codes?

USER: My source airport code is ATL and the destination airport code is PHX.

ASSISTANT: Wait a while, I will check and inform you.

USER: Ok, but please make sure that the price limit does not exceed 500.

ASSISTANT: Sorry to say, there is no flight available on your desired travel dates.

USER: Ok, no issues. I will try another alternate way to complete my trip.

ASSISTANT: Thank you for opting us.

USER: You are welcome.