Hi.
Hello, how can I help you today?
I want to change my destination airport code in my existing reservation, can you please help me out?
Let me know your name to check your reservation?
Sure, my name is John Clark.
Ok, please wait a moment.
Ok, take your time.
 I have checked in reservation list to change your ticket, but could not find any reservation with your name. Thank you for waiting.
It's ok, thank you for the information.
Thank you for choosing us.