You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I serve you?

USER: I would like to change my existing reservation which was made on the name of Carol Nelson. Can you help me with it?

ASSISTANT: Sure. Please, wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: That's ok, thank you for the response.

ASSISTANT: Thank you for opting us.