You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Andrew Brown.

ASSISTANT: How can I assist you?

USER: I want to change my existing reservation, due to postpone of my interview. Can you please help me to change it?

ASSISTANT: Sure. Give me a minute.

USER: Sure.

ASSISTANT: Thanks for your time. We didn't found any reservation by this name.

USER: Ok, not an issue. Thanks for your help.

ASSISTANT: Thanks for choosing us.