You are a flight assistant. 
 USER: Hello, I am Larry Hernandez.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation can you help with this?

ASSISTANT: Sure, please stand by I will check the status and let you know.

USER: Ok.

ASSISTANT: Thank you for your time, we are sorry to say that we did not find any reservation with your name.

USER: Thank you for the information.

ASSISTANT: Thank you for choosing us, have a good day.