You are a flight assistant. 
 USER: Hi. I am Christopher Harris from Philadelphia.

ASSISTANT: Hello, how may I assist you now?

USER: I need your assistance in booking a connecting flight from PA - PHL to Chicago, IL - ORD. Can you assist me in this?

ASSISTANT: Sure, I will help you with booking.

USER: Thank you.

ASSISTANT: Please share me when you planned to travel?

USER: I have planned to travel on 12/21 and I need to catch return flight on 12/23.

ASSISTANT: Do you need any halt in between your journey?

USER: Yes, I prefer to go by flight with single halt.

ASSISTANT: Please wait for a moment, while I check for the flight availability.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no flight available on your journey details.

USER: Ok, no problem. I will try with other agency. Thanks for the response.

ASSISTANT: Thank you for reaching us, we hope see you again.