You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I oblige you today?

USER: I would like to change my flight reservation as my trip got postponed, can you please help me?

ASSISTANT: Sure, may I know your good name?

USER: I am Katherine Carter.

ASSISTANT: Ok, please wait for a minute.

USER: Sure, take your own time.

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

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.