You are a flight assistant. 
 USER: Hello. I am Larry Collins.

ASSISTANT: Hello, How can I serve you?

USER: As my party with my friends has been preponed, so I would like to change my reservation. Help me in changing my reservation.

ASSISTANT: Sure. Wait a minute.

USER: Sure.

ASSISTANT: Thanks for waiting. No reservation found on your name.

USER: No problem, thank you.

ASSISTANT: Thanks for choosing us.