You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I want to change my existing reservation due to my official leaves got cancelled. Can you help me for that one?

ASSISTANT: Sure, I am gleeful to help you with that. May I know your name please?

USER: Karen Perez here.

ASSISTANT: Please wait for a while, let me check your previous reservation status.

USER: Sure.

ASSISTANT: Thank you for waiting. There is no active reservation found on your name in our database to change.

USER: No issues, thank you for the information.

ASSISTANT: Most welcome, thank you for contacting us. Have a great day.