You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: I'm Raymond Allen. I want to visit a historical place in Boston.Can you book a ticket from PA - PHL to MA - BOS?

ASSISTANT: Sure Raymond, can I know the dates of travel?

USER: My departure is on 11/25 and return is on 11/27. The connection limit is 1.

ASSISTANT: Hold on for a moment.

USER: Sure.

ASSISTANT: I'm sorry Raymond, there are no flights matching your preferences.

USER: That's not a problem. Thank you for your help.

ASSISTANT: Thank you, have a good day.