You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I want to alter my reservation due to post pone of my sister's engagement, can you help me with it?

ASSISTANT: Sure, may I know your name please?

USER: Reservation was done by the name Paul Collins.

ASSISTANT: Ok, please wait for a moment, I will check and get back to you.

USER: Ok.

ASSISTANT: Sorry, there was no reservation found with your name.

USER: Fine, thanks for the response.

ASSISTANT: Thank you for opting us.