You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER:  Owing to an emergency, I want to change my reservation. Can you please help me with that?

ASSISTANT: Let me know your name to check your reservation?

USER: James Walker here.

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.