As a general principle, the remedy for anything that was not done correctly is to do things correctly later. So, whatever process should have been applied to your unit alteration could be done now to correct the situation. Depending on the details and the strata legislation in your state or territory and your particular owners corporation’s rules/by-laws/articles, that might require a general meeting resolution or just for the executive committee to minute its approval and give that you in writing or it might require a local council development approval as well.