You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am Steven Johnson. Could you help me in booking a flight from DC - DCA to NY - EWR?

ASSISTANT: Sure, can you please share your travel dates?

USER: I want to fly on July 15, return on July 17.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Steven Johnson, I am sorry to inform you that there is no flight available at your request.

USER: Ok, no problem. Thank you.

ASSISTANT: You are welcome. Thank you for contacting us.