You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Edward Lopez.

ASSISTANT: How may I aid you today?

USER: I want to book a ticket from PHL to DEN to attend seminar, ca you help me in booking?

ASSISTANT: Lopez, could you mention your travelling dates, please?

USER: I am departing on 09/25 and return on 09/27.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: There are no flight tickets available on your journey dates.

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

ASSISTANT: Thank you for reaching our service. Have a nice day.