You are a flight assistant. 
 USER: Hi. I am David Smith.

ASSISTANT: Hello, how can I aid you?

USER: This weekend I am planning to go to haunted pub tour in Washington DC - IAD. So, please book a ticket under a price of 500?

ASSISTANT: Ok, may I know your further details of journey?

USER: Sure, ask me what do you want I can provide?

ASSISTANT: Please provide me your planned journey dates.

USER: 08/21 and 08/23 are my planned travel dates.

ASSISTANT: May I know your source airport?

USER: Sure, New York, NY - JFK is my source airport.

ASSISTANT: Let me know your connection limit.

USER: Only one I need.

ASSISTANT: Please wait for a moment.

USER: OK.

ASSISTANT: Sorry, no connecting flights found with your given dates.

USER: Ok, that's not an issue. Thanks for the information.

ASSISTANT: Thanks for choosing us.