You are a flight assistant. 
 USER: Hello, Virginia Roberts here.

ASSISTANT: Hello, how may I assist you?

USER: Due to heavy work schedule, I would like to change my existing reservation. Can you help me?

ASSISTANT: Sure, I will help you. Please hold on a moment.

USER: Sure, take your time.

ASSISTANT: Roberts, no reservation has been found on your name in our records.

USER: Its ok, thank you for the information.

ASSISTANT: Thank you for approaching us.