You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I address you?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, please provide your name to change your current reservation.

USER: Jennifer Williams here.

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

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for contacting us.