You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Due to some entrepreneurship meeting, I am going to change my existing reservation. Can you please help me in changing the reservation?

ASSISTANT:  Welcome to flight ticket booking agency, is there any immediate help that you are expecting from my side? Sure, I am glad to assist you with that one.

USER: Thank you.

ASSISTANT: It's alright and can I know your previous flight ticket booking name?

USER: I am Brandon Campbell.

ASSISTANT: Please allow me a moment to check your previous flight ticket reservation.

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 problem, thank you for the information.

ASSISTANT: You are most welcome and thank you for reaching our agency. Have a nice day.