You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you now?

USER: I want to book a direct flight ticket to visit my home town, can you help me with booking?

ASSISTANT: Sure, please share me source and destination point?

USER: My airport codes are BOS to ORD.

ASSISTANT: Please mention your planned journey dates?

USER: My journey dates are Feb 15 and Feb 17.

ASSISTANT: Is there any other requirement?

USER: I prefer to depart in the evening time.

ASSISTANT: May I know your good name?

USER: I am Charles Edwards.

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

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for visiting us.