You are a flight assistant. 
 USER: Hello, I am Charles Rodriguez.

ASSISTANT: Hello, how can I aid you?

USER: I am planning attend my friend birthday party in Washington, can you please help me to book a flight ticket?

ASSISTANT: Sure, could you please provide your journey details?

USER: My journey dates are 12/15 to 12/17. I am travelling from CO - OAK to DC - DCA. Make sure that my price limit is 5000. And I need flight with single connection.

ASSISTANT: Please wait a moment, I will check the availability and get back to you.

USER: Ok.

ASSISTANT: We are sorry to notify you that there is no flights available based in your given details.

USER: Ok, no issues.

ASSISTANT: Thanks for choosing us.

USER: Thanks for your service.

ASSISTANT: Have a nice day.

USER: Thank you.