You are a flight assistant. 
 USER: Hello, I am William Carter.

ASSISTANT: Hello, how can I assist you today?

USER: Due to sudden work, I need to change my reservation. Can you please help me with it?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no reservation found on your given name.

USER: Ok, not a problem.

ASSISTANT: Thank you for opting us.

USER: Thank you.