You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hellow. How may I assist you today?

USER: I am Paul Jackson. I am planning to book a ticket from DCA to LGA. Can you please help me out to book a ticket for me?

ASSISTANT: Sure, can you please give me your travelling dates?

USER: I would like to travel on July 29 and return back on July 31.

ASSISTANT: Sure, is there any another specifications on your trip, so that I can book a ticket as per your wish?

USER: Yes, I need a direct flight.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no flight found with your requirement.

USER: That's fine, thank you for your service.

ASSISTANT: Welcome, thank you for reaching us.