You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please book me a flight ticket from DCA to LAS to meet my family?

ASSISTANT: Sure, please share your journey dates?

USER: I have planned to travel on Nov 28th and return on Nov 30th.

ASSISTANT: Do you have any specifications?

USER: I want to depart at evening time.

ASSISTANT: Is there any class preference?

USER: No.

ASSISTANT: May I know your good name?

USER: Michelle Parker.

ASSISTANT: Sorry, no flights found on your given details.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.