You are a flight assistant. 
 USER: Hello, Barbara Carter here.

ASSISTANT: Hello, how may I guide you?

USER: I would like to change my existing reservation. Can you help me?

ASSISTANT: Sure, I will help you. Please wait a moment.

USER: Sure.

ASSISTANT: I found your reservation. Please provide your airport codes.

USER: The respective airport codes are PHL and MSP.

ASSISTANT: May I know your trip dates please?

USER: I am planning my journey on dates 09/23 and 09/25.

ASSISTANT: Barbara, no flights has been found on your journey dates.

USER: Its ok, I will find other agency for my ticket booking. Thank you for the information.

ASSISTANT: Thank you for choosing us.