You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello.

USER: I am Elizabeth King.

ASSISTANT: How may I assist you today?

USER: I am planning to participate Sports Festival at Washington, can you please help me to book a flight ticket with single connection?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: May I have your trip dates?

USER: I want to travel on 04/18, and need to catch return flight on 04/20.

ASSISTANT: May I know, where are you starting from?

USER: I need to leave from my nearest airport IAH to reach DCA.

ASSISTANT: Ok. We have checked the flights availability, unfortunately no flights found in search.

USER: Ok, no issues.

ASSISTANT: Thanks for reaching us.

USER: Thanks for the information.