There are numerous synonyms for the phrase "had second thoughts." These include, but are not limited to, "reconsidered," "retreated," "changed one's mind," "regretted," "doubted," "re-evaluated," "wavered," "hesitated," "rethought," "thought twice," and "had second guesses." Each of these phrases implies a degree of certainty and conviction in one's initial decision followed by a subsequent shift in one's belief. While expressing doubt or changing one's mind can be perceived as weakness, having second thoughts can also signify a thoughtful and deliberate approach to decision-making and problem-solving.