You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you?

USER: Can you please reserve me a flight ticket from DCA to JFK?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: Thank you, my trip dates are 10/23 - 10/25.

ASSISTANT: Do you have any preferences?

USER: My return time should be in the evening.

ASSISTANT: May I know your name please?

USER: Timothy King here.

ASSISTANT: Sorry, there is no flights available with your requirements.

USER: No issues, thank you.

ASSISTANT: You are welcome, have a nice day.