You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation which is done recently due to some problems, can you please help me in this?

ASSISTANT: Sure, I am here to help you with that, can I know your good name to proceed further?

USER: Sure, my name is Janet Turner.

ASSISTANT:  I am very sorry to inform you that there is no reservation found under your name in our database.

USER: Ok, no problem. Anyways, thank you for your service.

ASSISTANT: Thank you for reaching us.