You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Sure, I can help you with that. May I know your good name please?

USER: I am Larry Martinez.

ASSISTANT: Ok, please wait I'll check your reservation status in our database.

USER: Sure.

ASSISTANT: Larry Martinez, there is no active reservation found under your name to do changes in that.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for choosing us, have a nice day.