You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

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

ASSISTANT: Sure, may I know your name?

USER: I am Samuel Nelson.

ASSISTANT: Ok, please wait a minute.

USER: Sure.

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

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

ASSISTANT: Thank you for reaching us.