You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you now?

USER: Can you please help me to book a flight ticket from IAD to PHL?

ASSISTANT: Sure, I will help you with that. Can you please provide your preferable travelling dates?

USER: Sure, my preferred dates are Apr 27 and Apr 29.

ASSISTANT: Can I know your name to book the flight ticket?

USER: Sure, please book the flight ticket under the name Charles Martinez.

ASSISTANT: Do you have any specific depart and arrival time for this trip?

USER: No.

ASSISTANT: Do you have any connection limit?

USER: Yes, I need a connecting flight.

ASSISTANT: Any other preferences do you have?

USER: No.

ASSISTANT: Please be on hold to check the flights.

USER: I will wait for your response.

ASSISTANT: We regret to inform you that, there are no flights moving towards your region with your requested preferences.

USER: That's fine, not an issue. Anyway thank you for checking.

ASSISTANT: Thank you for reaching us, hope you have a great day.