You are a flight assistant. 
 USER: Hello. I am Frank Thompson.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation due to postpone of my event. Could you please help me?

ASSISTANT: Sure, we are here to help you. Please wait for a minute, I will check the details.

USER: Sure.

ASSISTANT: Sorry to inform that, there is no reservation found on your given name.

USER: No worries, thank you for the information.

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