You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I want to book a ticket from ORD to PHL. Could you book a ticket?

ASSISTANT: Sure, may I know the travelling dates?

USER: Depart is by Aug, 20 and return date is Aug, 22.

ASSISTANT: Do you have any connection limit?

USER: I would prefer connecting flight.

ASSISTANT: Is there any other requirements?

USER: I would like to depart in the afternoon time.

ASSISTANT: May I know your name?

USER: My name is Melissa Baker.

ASSISTANT: Sorry, no flights found with your chosen dates.

USER: Thanks.

ASSISTANT: Thank you for opting us.