You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I support you for the day?

USER: I am Brenda Robinson. Due to my health problem I want to change my reservation, can you please help me that?

ASSISTANT: Sure, I am here to help you. Please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, we found no reservation on your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us. have a great day.