You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: Could you help me to amend my existing reservation?

ASSISTANT: Sure, may I know your good name?

USER: I am Lisa Parker.

ASSISTANT: Ok, please wait for a minute.

USER: Sure.

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

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for choosing us.