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

ASSISTANT: Hello, how may I help you today?

USER: Owing to an emergency I want to change my existing reservation, can you help me with that?

ASSISTANT: Sure, please wait for a moment I will get back to you.

USER: Ok.

ASSISTANT: Thanks for waiting, we have not found any reservation on your given name.

USER: Ok, no issues. Thanks for your information.

ASSISTANT: Thanks for choosing us.

USER: Thank you.