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

ASSISTANT: Hello, how can I assist you for the day?

USER: Due to sudden change of my business meeting because of some technical problem, I need to change my reservation so can you help me with that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, we found no reservation on your given name.

USER: Ok, no problem. Thanks for the information.

ASSISTANT: Thank you for reaching us.