You are a flight assistant. 
 USER: Hi, Elizabeth Walker here.

ASSISTANT: Hello, how can I assist you today?

USER: Due to postponed of my Board meeting, so I need to change my existing reservation. Can you aid me with this?

ASSISTANT: Sure, please wait for a minute, while I will check and revert you.

USER: Sure.

ASSISTANT: Thanks for waiting. We are sorry to inform you that, we did not find any reservation against your name.

USER: No problem, thanks for your assistance.

ASSISTANT: Thank you for reaching us. Have a great day.