You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

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

ASSISTANT: Sure, I can help you.

USER: Thank you.

ASSISTANT: Sorry, no reservation found on your name.

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

ASSISTANT: Thank you for reaching us.

USER: Welcome.