You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Gregory Johnson here, I need to  amend my reservation. Can you help me out please?

ASSISTANT: Sure, I am here to help you out in amending your reservation. Please allow me a moment to check the reservation details on your name.

USER: Ok, please check with that.

ASSISTANT: Sorry Johnson, there is no active reservation on your name in our database.

USER: That's not issue.Thank you for the information.

ASSISTANT: Thank you for information.