You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

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

ASSISTANT: Yes, I can help you. Can I know your name for checking?

USER: Sure, my name is Gregory Moore.

ASSISTANT: Give me a moment.

USER: Sure, take your time.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: Ok, no problem. Thank you for your service.

ASSISTANT: Thank you for consulting us.