You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: Anna Lopez is here. I would like to change my exiting reservation, due to postpone of my seminar. Will you please assist me in changing my existing reservation?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for approaching us.