You are a flight assistant. 
 USER: Hello. Barbara Carter is here.

ASSISTANT: Hello, how can I guide you at this moment?

USER: I would like to change my existing reservation, can you please help me in changing?

ASSISTANT: I am here to assist you about your request.

USER: Thank you.

ASSISTANT: Please be on hold for a while to check our booking list.

USER: Sure.

ASSISTANT: I apologise to say this Barbara Carter, there is no active reservation with your name.

USER: Ok, no worries at all. Thank you for your information.

ASSISTANT: You are welcome, thank you for reaching us. Hope you have a nice day ahead.