You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: In my existing reservation I need to do some modifications, please help me in that.

ASSISTANT: Sure, may I know your name so that I can help you easily.

USER: Sure. My name is Brian Jones.

ASSISTANT: Ok Jones, please wait a moment I will check your previous reservation whether it is existed or not. Thanks for your time, there is no reservation under your name.

USER: It's ok. Thank you.

ASSISTANT: Welcome, thanks for consulting us.