For what it’s worth, I don’t think changing a political stance should be considered “flip-flopping” unless it’s done for a self-serving purpose. Reevaluating should be considered an attempt to learn and grow. That’s why wisdom is often (but not always) associated with age and/or experience.
Unfortunately in my experience the older the person the less likely that they will be open to re-evaluating their core beliefs and political stance. Wonder if there is a research on the subject.