You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I would like to change my destination airport code, please help me in changing my existing reservation.

ASSISTANT: Sure, Let me know your name to check your reservation?

USER: My name is Shirley Allen.

ASSISTANT: Thank you for waiting. I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for choosing us.