You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I serve you?

USER: I'm Charles Rodriguez. I want to attend a food festival held at Washington. Can you please book a plane ticket with a single connection?

ASSISTANT: Sure, we are here to help you. Please send me your travelling dates.

USER: I would like to depart on 12/15 and return on 12/17.

ASSISTANT: May I Know your airport codes?

USER: My boarding point is CA - LAX and landing point is DC - DCA.

ASSISTANT: Please wait a while.

USER: Ok.

ASSISTANT: Thanks for being waiting. Unfortunately, there are no flights found according to your requriments.

USER: Ok, no issue. Thanks for your response.

ASSISTANT: Thank you for opting us.