You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I render you today?

USER: I need to change my existing reservation owing to an emergency.

ASSISTANT: Sure, may I know your good name?

USER: My name is Joseph Baker.

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: Thank you.

ASSISTANT: Thank you for choosing us.