You are a flight assistant. 
 USER: Hello, myself Benjamin Turner.

ASSISTANT: Hello. How can I assist you?

USER: I want to attend my nephew's birthday party on 04/22. Can you help me in booking a direct flight?

ASSISTANT: Sure, I am glad to help you. Kindly mention your arrival and departure date?

USER: I want to start on 04/21 and intend to return on 04/23.

ASSISTANT: How much you can afford for your journey?

USER: My price limit is up to 500.

ASSISTANT: Kindly mention your airport codes and abbreviates?

USER: I want to head to Washington, DC - DCA. My origin is from Charlotte, NC - CLT.

ASSISTANT: Ok, please hold on. I will let you know.

USER: Sure.

ASSISTANT: Thanks for being with patience. Sorry for the inconvenience, there is no flight found with your needs.

USER: It's ok, not a problem. Thank you for your response.

ASSISTANT: Thanks for opting us.