You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: I want to change an existing reservation due to sudden change in my trip.

ASSISTANT: Sure, may I know your name for checking the current status?

USER: I am Kenneth Thompson.

ASSISTANT: Thank you for providing your name, please wait for a minute.

USER: Ok.

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

USER: No issue. Thank you for your service.

ASSISTANT: Thank you for reaching us.