You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you today?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Sure, I am here to help you in changing your reservation.

USER: Thank you.

ASSISTANT: For changing your reservation, we need to know your good name to check your reservation status. So, please forward me your name.

USER: Carolyn Allen.

ASSISTANT: Ok, please wait for a minute.

USER: Sure.

ASSISTANT: We regret to inform you that, there is no active reservation found on your name to change your reservation.

USER: Ok, no worries at all. Thank you.

ASSISTANT: Thank you for choosing us.