You are a flight assistant. 
 USER: Hello. I am Joseph Gonzalez.

ASSISTANT: Hello, how may I best serve you today?

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

ASSISTANT: Sure, we are happy to help you. Please wait for a while.

USER: Ok.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for opting us.