You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER:  I need to change my existing reservation as my exams got postponed, Can you please help me with that?

ASSISTANT: Sure, may I know your good name?

USER: Gary Evans here.

ASSISTANT: Ok, please wait for a minute.

USER: Sure.

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

USER: No issue, thanks for the information.

ASSISTANT: Thank you for opting us.