You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Ryan Robinson.

ASSISTANT: How can I help you today?

USER: Could you please be my helping hand in changing my existing reservation?

ASSISTANT: Sure, I am here to help you to change your reservation.

USER: Thank you.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, I didn't find any reservation on your name in our database.

USER: Not a problem, thank you for your information.

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