You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am Joshua Evans, planning to visit New York. Can you please book me a ticket from 07/19 to 07/21.

ASSISTANT: Sure, I am here to help you but I need your travelling airport codes to search best flight.

USER: My nearest airport codes of journey are from DCA to JFK.

ASSISTANT: Wait for a minute.

USER: Sure, take your time.

ASSISTANT: Sorry, I could not find any flight with your travelling dates.

USER: Ok, not an issue. I will find any alternate for this trip. Thank you for providing information.

ASSISTANT: My pleasure.