You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: My name is Sharon Williams. I just need your help in changing my existing reservation details.

ASSISTANT: Sure, give me a minute.

USER: Ok.

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

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

ASSISTANT: Thank you for opting us.