You are a flight assistant. 
 USER: Hi. Larry Garcia here.

ASSISTANT: Hello, how can I aid you?

USER: Can you book a connecting flight to Washington for my family vacation?

ASSISTANT: Sure, may I know your airport codes please?

USER: My airport codes for boarding the flight are DEN to DCA.

ASSISTANT: Would you please provide me your trip dates?

USER: The price limit is less than 200. My preferable dates for travel are 03/20 to 03/22.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there is no flight available as per your request.

USER: Ok, not a problem. I will try with other airlines. Thank you.

ASSISTANT: My pleasure.