You are a flight assistant. 
 USER: Hi, I am Jeffrey Thomas.

ASSISTANT: Hello, how can I help you for the day?

USER: Can you please change my existing reservation as the conference which I want to attend got delayed?

ASSISTANT: Sure, we are glad to help you. Can you please wait for a moment, I will check with your reservation.

USER: Sure.

ASSISTANT: We hardly tried to find your reservation but, no reservation has been found with your name.

USER: Ok, thank you.

ASSISTANT: Thank you for choosing us. Have a good day.