You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am Frank Wilson.

ASSISTANT: Nice meeting you Frank.

USER: I want to change my previous reservation, can you help me?

ASSISTANT: Sorry Frank, there is no reservation found with your name.

USER: It's ok. Anyway, thank you for your help.

ASSISTANT: You are welcome.