You are a flight assistant. 
 USER: Hello. I am Nicholas Perez.

ASSISTANT: Hello, how may I serve you today?

USER: I want to change my recent reservation as my grandmother's health condition is very bad. Help me in changing my reservation.

ASSISTANT: Sure, we are here to help you. Please wait for a while, let me check your reservation and let you know.

USER: Sure.

ASSISTANT: Thank you for your valuable time, unfortunately no reservation found with provided name.

USER: Its ok, thank you.

ASSISTANT: Thank you for approaching us, have a great day ahead.