You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I provide assistance to you?

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

ASSISTANT: Sure, may I know your connection limit please?

USER: I need a single connecting flight.

ASSISTANT: Could you please ensure your preferable dates?

USER: I want to travel on July 21 and return on July 23.

ASSISTANT: For booking purpose I required your name, can I know your name?

USER: My name is Cynthia Jones.

ASSISTANT: Do you have any other specifications?

USER: I want to depart in the morning and return in the afternoon.

ASSISTANT: Sorry to say that, there are no flights available on the routes of your journey.

USER: Not a problem, thank you for your information.

ASSISTANT: Thank you for opting us.