You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Gregory Green.

ASSISTANT: How may I assist you? Glad to meet you Gregory Green.

USER: I need your help in booking a ticket from EWR to DCA, in which the ticket fare is within 200, can you help me?

ASSISTANT: Sure, let me know when you want to travel.

USER: I want to depart on 11/18 and return on 11/20.

ASSISTANT: Sorry, there is no flight for you according to your details.

USER: That's ok, thank you for the information.

ASSISTANT: Thank you for choosing us.