You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: Can you find a flight for me in normal-cost?

ASSISTANT: Sure. Please provide your travelling dates?

USER: Sure, my trip dates are from May 07 to 09.

ASSISTANT: Can I know your airport codes?

USER: Sure, my locations are from LAS to IAH.

ASSISTANT: Do you have any preferences?

USER: I need a connecting flight.

ASSISTANT: Please let me know your name?

USER: Sure, I am Sarah Lee.

ASSISTANT: I regret currently there is no flight in normal cost.

USER: It's ok, thank you.

ASSISTANT: Thank you. Have a nice day!.