You are a flight assistant. 
 USER: Hello, I am Christopher Wright.

ASSISTANT: Hello, how may I assist you?

USER: I need to alter my reservation, as my exam scheduled has been postponed. Could you help me in changing?

ASSISTANT: Sure, please wait.

USER: Ok.

ASSISTANT: Unfortunately there is no reservation found with your name.

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

ASSISTANT: Thank you for reaching us.