You are a flight assistant. 
 USER: Hello. My name is Donna Rodriguez.

ASSISTANT: Hello. How can I assist you today?

USER: I want to do some changes in my existing reservation, can you help me for that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Sorry, I didn't find any reservation found on your name.

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

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