You are a flight assistant. 
 USER: Hello. My name is Mark King.

ASSISTANT: Hello, how can I assist you for the day?

USER: I want to book a flight ticket to my brother in PHL. Can you please help me for booking from IAD?

ASSISTANT: Sure, I am here to help you.

USER: Ok.

ASSISTANT: When you are willing to travel?

USER: My planned journey dates are 10 and 12 on the month of may.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, we found no flights on your given dates.

USER: Ok, thanks for your information.

ASSISTANT: Thank you for reaching us.