You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I just need your help in changing my existing reservation details.

ASSISTANT: Sure, I am here to help you. Can I know your name please.

USER: My name is Catherine Collins, please check with this name.

ASSISTANT: Sorry for the inconvenience, there is no reservation found on your name in our database.

USER: Not an issue, thank you for the information.

ASSISTANT: Thank you for reaching us.