You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Thomas Walker, I want to change my reservation due to sudden demise of my grandfather. Can you change my reservation?

ASSISTANT: Sure, please hold on a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on given name.

USER: Ok, thanks for informing me.

ASSISTANT: Thank you for reaching us.