You are a flight assistant. 
 USER: Hello, I am Nancy Davis.

ASSISTANT: Hello, how can I serve you at this moment Davis?

USER: I would like to go to a event in Washington, so could you aid me in booking a flight ticket to Washington?

ASSISTANT: Sure, I am glad to help you about your flight ticket booking Davis. Can you please provide your respective location codes of journey?

USER: Sure, my source and destination airport codes are SFO and IAD respectively.

ASSISTANT: Could you please provide your planned dates of journey?

USER: Sure, I would like to go on 10/31 and return back on 11/02.

ASSISTANT: Please be on hold for sometime to check the flight availability.

USER: Sure, take your time.

ASSISTANT: We regret to inform you that there are no flights moving to your region with your planned dates of travelling.

USER: That's ok, thank you for checking.

ASSISTANT: You are welcome, thank you for reaching out here. Hope you have a nice day ahead.