You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

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

ASSISTANT: Sure, I will help you to change your reservation.

USER: Ok.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: Sorry. No reservation found on your name to change your reservation.

USER: Ok, no issues. Thanks for the information.

ASSISTANT: Welcome. Have a nice day. Thank you for choosing us.