You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: My name is Brenda Johnson. I want to change my reservation, can you help me for that?

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

USER: Sure, take your time.

ASSISTANT: Sorry, no reservation found on your name.

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

ASSISTANT: Welcome, have a nice day.