You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: I am planning to visit Los Angeles, can you please book me a ticket from DCA to LAX?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: I am planning my journey on the dates of Apr 17 and Apr 19.

ASSISTANT: Ok, could I have your name please?

USER: My name is Dorothy Garcia.

ASSISTANT: Ok, do you need direct or connecting flight?

USER: I prefer direct flight.

ASSISTANT: Ok, may I know your airline preference?

USER: No, I am comfort with any airlines.

ASSISTANT: Ok, please allow me a moment.

USER: Please ensure that return flight time is in the afternoon time.

ASSISTANT: Sorry, there is no flight with your requests.

USER: Ok, not an issue. Thank you for providing information.

ASSISTANT: You are welcome, have a great day.