You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Can you please change my existing reservation as my plan to go for holiday trip got postponed?

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

USER: I am Cynthia Rodriguez.

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

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Welcome Cynthia Rodriguez.