You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER:  I am Kathleen Johnson want to change my reservation due to prepone of meeting.

ASSISTANT: Sure, please wait for a moment I will check your details and proceed further.

USER:  Can you help me in changing?

ASSISTANT: Yes, I found a reservation on your name. Can you please provide your new airport codes?

USER: I will depart from TX-DFW to CO-DEN.

ASSISTANT: Ok, may I know your travelling dates?

USER: My travel dates are 08/27 and 08/29.

ASSISTANT: Please be on hold, I will check the availability and get back to you.

USER: Ok.

ASSISTANT: Ok, there is a flight 1015 in UA airline matching your details with price 200. Shall I proceed?

USER: You can proceed.

ASSISTANT: Ok, your booking is done.

USER:  Thank you for booking.

ASSISTANT: You are welcome, have a safe journey.