You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I need to change my existing reservation due to postpone of my document verification in office. Can you please help me with this?

ASSISTANT: Sure, can I know you name?

USER: I am Jack Roberts.

ASSISTANT: Please hold on a moment.

USER: Sure.

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

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for reaching us.