You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I want to attend a Seminar in Philadelphia. Can you please help me for booking the flight ticket?

ASSISTANT: Sure. May I know your class preference please?

USER: I want to prefer economy class.

ASSISTANT: Tell me your name please?

USER: My name is Donna Hall.

ASSISTANT: Now share your airport codes and travel dates please?

USER: My travelling dates are July 14 and July 16.

ASSISTANT: Ok.

USER: My airport codes are CLT and PHL.

ASSISTANT: May I know your connection limit please?

USER: I need single connecting flight.

ASSISTANT: Do you have any other preferences?

USER: No.

ASSISTANT: Please wait.

USER: Ok.

ASSISTANT: Thanks for waiting.

USER: My pleasure.

ASSISTANT: Sorry to say that presently there are no flights available in economy class.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you.