You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,.

USER: I am John Martinez.

ASSISTANT: How shall I assist you?

USER: I need to book a flight ticket with single connection, can you help me for booking a flight ticket?

ASSISTANT: Definitely. Please provide your travelling codes.

USER: I would like to travel from PA-PHL to NY-EWR.

ASSISTANT: May I know your dates of travel.

USER: My departure date on 11/21 to 11/23.

ASSISTANT: There is no flight with your requirements.

USER: Ok, Thanks for your information.

ASSISTANT: Thanks.