You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: Can you please help me in booking a flight ticket from DCA to PHX?

ASSISTANT: Sure, may I know your good name?

USER: Myself Steven Lopez.

ASSISTANT: Could you please share your journey dates?

USER: I want to fly on Sept 12 and return on Sept 14.

ASSISTANT: Do you have any preferences?

USER: I would like to return in the evening time.

ASSISTANT: Sorry, there are no flights available as per your requirements.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for choosing us.