You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I want to fly DC - DCA on 04/22. Can you help me to book my flight ticket?

ASSISTANT: Sure, please provide your departure date.

USER: My departure date is 04/22.

ASSISTANT: Please provide your destination airport code.

USER: My destination airport code is DC - DCA.

ASSISTANT: Will you provide your source code and return date?

USER: My source is MN - MSP. And, my return date is 04/24.

ASSISTANT: May I know your name please?

USER: Myself Cynthia Martinez.

ASSISTANT: Unfortunately, there is no flights found under your details.

USER: Ok, it's fine. Thank you for your service.

ASSISTANT: Welcome, have a great day.