You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Karen Adams.

ASSISTANT: How may I assist you?

USER: Can you please change my existing reservation as my plan to meet my friend got postponed?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please wait a moment I will check the reservation list.

USER: Sure.

ASSISTANT: Sorry Karen Adams, there is no active reservation on your name.

USER: Ok, not an issue. Thank you for the information.

ASSISTANT: Thank you.