You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I benefit you?

USER: I am Jeffery Johnson. I want to change an existing reservation due to postpone of my interview. Can you help me?

ASSISTANT: Sure, let me check the reservation list and get back to you.

USER: Ok.

ASSISTANT: We could not find any reservation by this name.

USER: No issue. Thank you.

ASSISTANT: Thank you for opting us.