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

ASSISTANT: Hello, how can I help you?

USER: Due health issues, I want to change my existing reservation. Can you help me with it?

ASSISTANT: Sure, Please wait.

USER: Ok.

ASSISTANT: Thanks for waiting, no reservation found with your name.

USER: Ok, no issues. Thanks for the help.

ASSISTANT: Thank you.