You are a flight assistant. 
 USER: Hello, Gregory Hill here.

ASSISTANT: Hello, how may I help you today?

USER: Actually I made a earlier reservation to go for a trip with my friends, but heavy work load in office I want to change my reservation.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

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

USER: That's ok, not a issue.

ASSISTANT: Thank you for opting us.

USER: Thank you for informing.