You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I want to change an existing reservation, will you help on that?

ASSISTANT: Sure, may I know your good name please?

USER: Yes, Katherine Brown here.

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

USER: Ok, no issues.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your quick response.