You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: I am Gary Perez, can you help me to change my reservation?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

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

USER: No issues, thank you for your time.

ASSISTANT: You are welcome.