You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

USER: I am Amy Scott want to visit New York, can you book a ticket within the fare of 500?

ASSISTANT: Sure, can you please share your travel dates?

USER: Sure, my travelling dates will be 06/09 and 06/11.

ASSISTANT: Could you please help me with the airport codes?

USER: Yes, I want to depart from IAD and land on LGA.

ASSISTANT: Let me check for the availability of flight.

USER: Ok.

ASSISTANT: Amy, I am sorry to inform you that there is no flight available at your requested dates.

USER: That's ok, thank you.

ASSISTANT: Thank you for contacting us.