You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Charles Baker, want to alter my recent reservation. Please help me out with that.

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name in our database to change.

USER: It's ok, thank you.

ASSISTANT: You are most welcome.