You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know what kind of serves are you looking?

USER: I am looking to book a flight ticket from DEN to JFK. Can you help me for booking a flight ticket?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: To check the flight availability we need to know your name, can you please share me your name?

USER: My name is Larry Allen.

ASSISTANT: On which dates do you like to leave and return?

USER: My travelling dates are Mar 23 and Mar 25.

ASSISTANT: At what time do you like to depart and return?

USER: I don't have any time limit.

ASSISTANT: Do you prefer any other specifications?

USER: I need a direct flight in my journey.

ASSISTANT: Sorry, there is no flight available at this moment.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for communicating us.

USER: Welcome.