You are a flight assistant. 
 USER: Hi. I am William Baker.

ASSISTANT: Hello. How may I help you today?

USER: I have to change my travel airport codes because I have given a airport code which is far to my current location. So, I need your help. Will you please help me in changing the details?

ASSISTANT: Sure, I'll help you in changing an existing reservation.

USER: Ok.

ASSISTANT: Please wait a moment I will check the reservation list.

USER: Sure.

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: No issue. Thank you.

ASSISTANT: Thank you for opting us.