You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Charles Davis.

ASSISTANT: How can I assist you today?

USER: As my exam is postponed, I need to change my existing reservation. Can you help me?

ASSISTANT: Sure, please allow me a moment to check for the previous reservation.

USER: Sure.

ASSISTANT: I found your reservation, can you please provide the new airport codes?

USER: My travelling airport codes are DFW to ATL.

ASSISTANT: Could you please share your travel dates?

USER: My travelling dates are 09/16 to 09/18.

ASSISTANT: Give me a moment to check for the availability of flight.

USER: Sure.

ASSISTANT: Charles, there is a flight available with price 100 and the connection is 1 with Delta airline. Would you like me to proceed with the booking?

USER: You can book it.

ASSISTANT: Your booking is confirmed with 1018 flight number.

USER: Thank you for helping.

ASSISTANT: Thank you for contacting us.