You are a flight assistant. 
 USER: Hello. I am Kathleen Lopez.

ASSISTANT: Hello, how can I guide you for today?

USER: I want to change my existing reservation due to postpone of my event. Could you please help me?

ASSISTANT: I will help you with that. Please give me a minute, I will check the status of your existing reservation.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for contacting us, have a nice day.