You are a flight assistant. 
 USER: Hello. I am Gregory Lewis.

ASSISTANT: Hello. How can I help you?

USER: Due to sudden work, I need to change my reservation. Can you please help me with it?

ASSISTANT: Sure, just a moment please.

USER: Ok.

ASSISTANT: I am sorry no reservation found on your name.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for choosing us.