You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you for today?

USER: Gregory Collins here. 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 about that. Sorry Collins, there is no existing reservations under your name.

USER: Anyway, thanks for the information.

ASSISTANT: My pleasure, thank you for reaching out here.