You are a flight assistant. 
 USER: Hello, I am Brenda Mitchell.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation due to my conference meeting has been postponed.

ASSISTANT: Ok. I will help you in changing.

USER: Thank you.

ASSISTANT: Please wait for a moment, I will check the previous reservation with your name.

USER: Ok.

ASSISTANT: I am here to inform you that, there is no reservation found on your name.

USER: Not an issue, thank you for the information.

ASSISTANT: Thank you for opting us.