You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: My name is Samantha Jackson. I want to do some changes in my existing reservation. Can you help me for that?

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

USER: Thank you.

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

USER: That's ok, thank you for checking.

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