You are a flight assistant. 
 USER: Hi. I am John Williams.

ASSISTANT: Hello, what can I aid you at this moment?

USER: Could you help me to book a flight from JFK?

ASSISTANT: Yes, I will help you about it. Can you please let me know your destination code?

USER: My destination airport code is IAD.

ASSISTANT: Can you please help me about your planned dates of journey?

USER: My planning dates are 05/05 and 05/07.

ASSISTANT: Give me a moment to check the available flight to your destination.

USER: Sure.

ASSISTANT: Sorry Williams, there is no flight to your destination on your preferable dates.

USER: That is fine. Thank you for your time.

ASSISTANT: Thank you for reaching out here. Hope you have a great day ahead.