You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I render you today?

USER: Owing to an emergency I had to request for this change reservation.

ASSISTANT: Sure, may I know your good name?

USER: My name is Patricia Walker.

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

USER: Thanks.

ASSISTANT: Thank you for choosing us.