You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your good name please?

USER: Sure, my name is Patricia Hill.

ASSISTANT: How may I assist you today?

USER: I have a plan to surprise my brother on his Birthday, so I need to book a flight ticket to Chicago, IL - ORD. Can you help me to book a ticket from Boston, MA - BOS?

ASSISTANT: Sure, could you please provide me your journey dates?

USER: Sure, I intend to fly on 10/11 to 10/13.

ASSISTANT: Let me know your price limit.

USER: Ok, I can afford upto 200.

ASSISTANT: Ok, please wait for a moment.

USER: Ok, I will wait for your response.

ASSISTANT: Thanks for waiting. Sorry, no flights found with your given dates.

USER: That's Ok. Thanks for your kind service.

ASSISTANT: Thanks for opting us.