You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I am Carol Hall. I want to change my existing reservation due to postpone of my client meeting.

ASSISTANT: Sure, please hold on. I will check your details and let you know the status.

USER: Sure.

ASSISTANT: Thank you for being on hold, there is no active reservation found on your name to do modification.

USER: No problem, thank you for your help.

ASSISTANT: Thank you for reaching us.