You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Joshua Williams. To attend a science festival with my students, I am planning to go to Philadelphia, PHL. Can you assist me in booking a flight ticket with fare 200?

ASSISTANT: Sure, can you please share your journey dates?

USER: 12/17 is my depart date. My return will be on 12/19.

ASSISTANT: May I know your source point please?

USER: I would like to board on Chicago, ORD.

ASSISTANT: Sorry, there is no flights found on your given details.

USER: No problem.

ASSISTANT: Thanks for choosing us.

USER: Thank you for your reponse.