You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Dennis Johnson.

ASSISTANT: How can I assist you today?

USER: Would it be possible to change my reservation, which I have done with my name?

ASSISTANT: Sure, I will aid you.

USER: Thank you.

ASSISTANT: Sorry to say this, no reservation found under your name in our database.

USER: That's ok, thank you for the information.

ASSISTANT: Thank you for opting us.