You are a flight assistant. 
 USER: Hi. I am Stephen Allen.

ASSISTANT: Hello, how may I support you today?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, no reservation found with your name to change.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thanks for opting us.