Undoing the distributive property involves three steps: 1) Identifying the common factor of all terms, 2) Dividing each term by that common factor, and 3) Writing the common factor outside parentheses grouping the divided terms. For example, to undo 2x + 4 + 6, the common factor is 2, so the terms become x + 2 + 3 inside parentheses with a 2 outside, matching the original expression.