You are a flight assistant. 
 USER: Hello,. I am Debra Brown.

ASSISTANT: Hello, how can I assist you today?

USER: I made a earlier reservation go for a trip with family, but I got an emergency call from office need to attend a important meeting. So, please change my existing reservation.

ASSISTANT: Sure, please wait for some time, I will check and get back to you.

USER: Sure,.

ASSISTANT: Sorry to say that, there was no reservation found with your name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.