You are a flight assistant. 
 USER: Hello. Margaret Lopez here.

ASSISTANT: Hello, how may I aid you out?

USER: Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, I am here to help you out. Please allow me a moment.

USER: Ok, I will wait.

ASSISTANT: Sorry Margaret Lopez, there is no active reservation on your name in our data base.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for reaching us,.