You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, do you need any help from us?

USER: I am Melissa Perez want to visit Atlanta, can you book a ticket from DFW to ATL?

ASSISTANT: Sure, please tell me your trip dates.

USER: Sure, my travelling dates will be 11/23 and 11/25.

ASSISTANT: Perez, there is no flight on your requested travelling dates.

USER: That's ok, thank you.

ASSISTANT: You are welcome.