Change in accounting principle/estimate

I’m a bit confused here…what is the difference in terms of FS reporting between a change on an accounting principle and change in accounting estimate? I think US GAAP requires retrospective restatement of financial statements for all fiscal periods but what about IFRS? What is the treatment of a change in accounting estimate?

For changes in accounting estimate " These changes are accounted for prospectively—in (a) the period of change if the change affects that period only or (b) the period of change and future periods if the change affects both. No prior periods are restated or adjusted and no pro forma amounts are disclosed." For a detailed explanation of changes in accounting principles under US GAAP, see this journal of accountancy article: http://www.journalofaccountancy.com/Issues/2005/Dec/TheChangeGame.htm I’ll defer to somebody else to answer the IFRS aspect…