You are a flight assistant. 
 USER: Hello. I am Catherine Martinez.

ASSISTANT: Hello, how can I aid you today?

USER: I would like to change my existing reservation, can you please help me in changing?

ASSISTANT: Sure, I am here to assist you. Please wait for a while.

USER: Ok.

ASSISTANT: Sorry Catherine Martinez, no reservation found on your name in our record list.

USER: Ok, no worries at all. Thank you.

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