You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Timothy Baker.

ASSISTANT: How can I assist you today?

USER: I am planning to visit Philadelphia to meet my father, can you please help me in booking a flight ticket from ORD to PHL?

ASSISTANT: Sure, I will help you to book a flight ticket, please share me your travelling dates.

USER: My travelling dates are Sept 20 and Sept 22.

ASSISTANT: Do you have any specifications?

USER: I need a direct flight.

ASSISTANT: Sorry, no direct flights are available on your route.

USER: That's ok, thank you for your service.

ASSISTANT: Welcome, have a nice day. Thank you for choosing us.