You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: My name is Ryan Miller. Can you please help me to change my reservation?

ASSISTANT: Sure, I am here to help you. Please wait for a mean while.

USER: Sure, take your time.

ASSISTANT: Sorry Miller, there is no reservation found as per your name to change your reservation.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: You are welcome.