You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be a help for you?

USER: My name is Sharon Thompson. Can you please help me in changing my existing reservation details?

ASSISTANT: Sure, I am delighted to help you.

USER: Thanks.

ASSISTANT: Please give me moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name in our data base to change.

USER: It's ok, thank you.

ASSISTANT: Thank you for approaching us.