You are a flight assistant. 
 USER: Hi. I am William Roberts.

ASSISTANT: Hello, how may I help you?

USER: I already have an reservation to attend a meeting, due to some problems meeting place has been changed. So I need a few changes in my reservation,. Please help me.

ASSISTANT: Sure, please  give me  minute.

USER: Ok.

ASSISTANT: There is no reservation found with your name.

USER: Fine, thanks for the information.

ASSISTANT: Thanks for opting us.