You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I would like to change my existing reservation, due to postpone of my meeting. Can you please help me in changing?

ASSISTANT: May I know your name to check your reservation status?

USER: Helen Gonzalez.

ASSISTANT: Ok, please be on hold. Sorry, there is no reservation found on your name to change it.

USER: Ok, no issues. Thank you.

ASSISTANT: Thanks for reaching us, have a good day.