You are a flight assistant. 
 USER: Hello, Raymond Smith here.

ASSISTANT: Hello, how can I assist you?

USER: I have planned to attend a workshop on robotics at Washington, DC-IAD. Could you help me with the booking?

ASSISTANT: Sure. Can you please provide the journey details?

USER: My source code is DC-DCA, my travelling dates are from 07/14 to 07/16.

ASSISTANT: Thanks for the information. Please wait for a moment.

USER: Sure.

ASSISTANT: Unfortunately, we did not found any flights.

USER: Ok, no issues.

ASSISTANT: Thanks for contacting us.

USER: Thank you.