You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I would like to change my existing reservation under the name of Jonathan Walker. Can you help me in this?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

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

USER: It's ok, not an issue. Thank you for your information.

ASSISTANT: Thank you.