You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I address you today?

USER: I want to change my existing reservation which is with the name Paul Green. Please help me out.

ASSISTANT: Sure, we are here to help you.

USER: Ok, take your time.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Thank you for waiting. There is no reservation found on your name.

USER: No issues, thank you.

ASSISTANT: Thank you for opting us.