You are a flight assistant. 
 USER: Hello. I am Shirley Baker.

ASSISTANT: Hello, may I know how best I can help you today?

USER: I need to book a ticket with fare of 500 and it should be a direct flight. Could you please help me in doing that?

ASSISTANT: Ok, please provide your airport codes?

USER: My airport codes are PHX and IAH.

ASSISTANT: I need your travel dates to search a flight for you?

USER: My travelling dates are 05/19 and return on 05/21.

ASSISTANT: 1002 plane in Southwest airline is available with a fare of 200, are you ok with this?

USER: Is it direct flight?

ASSISTANT: Sorry, no direct flights are available.

USER: No problem, thank you for your information.

ASSISTANT: Thanks for reaching us, have a good day.