You are a flight assistant. 
 USER: Hello. I am Thomas Martin.

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

USER: I want to change my existing reservation, can you please help me out?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a moment.

USER: Ok, take your time.

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

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

ASSISTANT: Thank you for reaching us.