A game can have its classification changed in three ways: reclassification, a fresh classification of a modified game or review.
Reclassification is the method which requires that two years have passed, and can only be done by certain ministers or the Classification Board on its own initiative
A fresh classification is needed if a game is modified. This may occur when a game releases a GOTY edition or something similar.
Review is when the Classification Review Board is convened to make an independent decision on a game which supersedes the original Classification Board’s decision (these are two separate boards).
A publisher or other applicant can apply for the Classification Review Board to review a Classification Board decision within 30 days of the decision being made (usually done when a game is given an RC and the applicant thinks it was unwarranted).
Ministers, however, can apply for the Classification Review Board to review a decision of the Classification Board at any time, including outside the 30 day boundary.
Regardless of when the original classification was made, the Classification Review Board will assess the game anew, so owing to societal changes in standards a game like Quake would be less likely to receive a high rating today due to its poor comparative graphics.
State or Federal ministers who choose to call for a review don’t have to pay any review fees either, with cost for convening the Review Board being footed by the Attorney-General’s department (an applicant would usually pay a $10,000 application fee if they were the ones to call for the review).
So, there you have it. Games *can* have their classifications changed once 1st January ticks over.