You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Charles Martinez here. Do you have any flight from DCA to ATL to attend a birthday party?

ASSISTANT: Sure, I am happy to help you. May I know your planned trip dates?

USER: My travel dates are 04/27 and 04/29.

ASSISTANT: Sorry to say that, there are no flight's available based on your travelling dates?

USER: It's ok, anyway thank you.

ASSISTANT: Thank you for reaching us.