You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I want to cancel my recent reservation owing to an emergency.

ASSISTANT:  Sure, I am here to help you. May I know your name to check with existing reservation?

USER: Thomas Walker.

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

USER: Thank you.

ASSISTANT: Thank you for choosing us.