You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I have made a reservation earlier, due to some issues I need to change my existing reservation. Can you please help me with this?

ASSISTANT: May I know your name please?

USER: My name is James Jackson.

ASSISTANT: Sure, I will help you James Jackson. Sorry, no reservation found in our database as per your preferences.

USER: Not a problem, thank you for checking.

ASSISTANT: Thank you.