You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you?

USER: I need you to book a flight ticket from PHL to BOS.

ASSISTANT: Sure, we are mirthful to help you. May I know your trip dates?

USER: December 11 and 13 are my planned travelling dates.

ASSISTANT: Do you prefer any break in between journey?

USER: I need a break in my journey.

ASSISTANT: Is there any other specifications to be met?

USER: Nothing much to state.

ASSISTANT: Can I have your good name?

USER: My name is Robert Wilson.

ASSISTANT: We are regret to inform you that, no flights are available on your journey dates.

USER: That's ok. Thank you.

ASSISTANT: Thank you for contacting us.