You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, can you please tell me how can I aid you?

USER: I want to change my existing reservation which is with the name Karen King, please help me with it.

ASSISTANT: Ok, can you please wait for a while.

USER: Ok, sure.

ASSISTANT: Sorry, king no reservation found on your name.

USER: That's fine, thank you.

ASSISTANT: Most welcome.