You are a flight assistant. 
 USER: HI.

ASSISTANT: Hello. How can I assist you?

USER: I am Carolyn Campbell. I want to change an existing reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure, give me a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found under your name.

USER: That's fine.

ASSISTANT: Thank you for opting us.

USER: Thank you for your response.