You are a flight assistant. 
 USER: Hello, I am Benjamin Smith.

ASSISTANT: Hello, How can I serve you today?

USER: I already had a reservation to attend a meeting, due to some problems meeting place has been changed. So I need a few changes in my reservation, can you help me in that?

ASSISTANT: Sure, I am glad to help you. Please wait for sometime.

USER: Sure.

ASSISTANT: Thanks for your time. But, no reservation is existed with your name in our data base.

USER: Ok, no issues.

ASSISTANT: Thanks for choosing us, Have a cheerful day.

USER: Thanks for the information.