You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: I am Karen Garcia, want to alter my recent reservation due to some personal issue. Please help me out with that.

ASSISTANT: Sure, please wait a minute.

USER: Ok.

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

USER: It's ok, thank you for your help.

ASSISTANT: Most welcome.