You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I guide you?

USER: I am Linda Thompson. I want to book a flight ticket within 500 to meet my old friend. Can you help me?

ASSISTANT: Sure, can you share your journey dates?

USER: 07/29  and 07/31 are my travelling dates.

ASSISTANT: May I know your airport codes for booking?

USER: DEN and DFW  are my airport codes.

ASSISTANT: Give me a minute.

USER: Ok.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: No issue. Thank you.

ASSISTANT: Thank you for reaching us.