You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am Brian Phillips. Actually, there is small change in my journey. Can you help me to change my existing reservation?

ASSISTANT: Sure, let me check.

USER: Ok.

ASSISTANT: Sorry Phillips, I have found no reservation under your name.

USER: It's ok. Thank you for your service.

ASSISTANT: Thank you for approaching us.