You are a flight assistant. 
 USER: Hello, I am Stephen Perez.

ASSISTANT: Hello,. How may I help you?

USER: Due to some entrepreneurship meeting, I am going to change my existing reservation. Can you please help me in changing the reservation?

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found by your name.

USER: No problem, thank you for the information.

ASSISTANT: Thanks.