The Treason of Isengard: Eru's Plan?

[davem]

Originally Posted by burrahobbit

I get to ask a question again too. How exactly does a person change the performance of a song if he wasn't in the room with the other people playing? How can I change what an orchestra does in New York if I live in Oklahoma? Even more, how would I change that orchestra in New York if it happened 50 years before I was born?

A live performance can be changed by one of the participants. Think Jazz. The Music was the 'composition', the creation/manifestation of Arda is the performance of that composition. Not all the performers may have been around when the piece was composed, but as long as they are around when it is being played they can alter it - especially if they have the express permission of the composer/conductor to do that very thing.