You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am Charles Allen. Can you please change my reservation?

ASSISTANT: Sure, please wait. I will check the reservation on your name and revert to you.

USER: Sure.

ASSISTANT: Sorry, we couldn't find any reservation on your name.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for reaching us.