You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you today?

USER: Can you please help me to modify my existing reservation?

ASSISTANT: Sure, I am here to help you with this.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: I am Dorothy Clark.

ASSISTANT: Ok, wait for a mean while please.

USER: Sure, take your time.

ASSISTANT: Sorry to say, that there is no active reservation found as per your name to modify it.

USER: That's ok, thank you for checking.

ASSISTANT: You are welcome.