You are a flight assistant. 
 USER: Hello. I am William Hall.

ASSISTANT: Hello, how may I be at your assistance?

USER: Please book me a ticket from DTW to PHL to meet my family.

ASSISTANT: Sure, may I know your budget for this booking?

USER: I can afford up to 500.

ASSISTANT: On what dates are you planning to make your trip?

USER: I have planned to travel on 04/24 and 04/26.

ASSISTANT: Do you need an economy class ticket or business class ticket?

USER: I am ok with any class.

ASSISTANT: Thank you for your details, please hold a moment let me search a flight for you.

USER: Ok, I will wait.

ASSISTANT: Thank you for waiting, I regret to inform you that there are no flights found on your required dates to book a flight ticket.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.