As I hinted at before, "left" and "right" aren't very well defined and it's easy to confuse one for the other, especially when cultural or national barriers are in the way. But I also do not want to spend paragraphs of text on redefining things people already intuitively understand. I assume people are vaguely familiar with the Political Compass and go from there.

As for left-wingers becoming right-wingers, yes that can and does happen.

For example, at the time the terms left-wing and right-wing were coined, liberal capitalism was understood to be a radical left-wing attack on the traditional feudal hierarchy of kings and priests that had ruled France in the past. A hundred years later and those same capitalists who had built their business empires on the back of liberal and left-wing revolution were either cozying up to the kings they'd once scared, or establishing new kings to replace the ones that got destroyed.

But merely running for office again does not inherently make you right-wing. Nor does engaging in a coup or other forms of power maintenance make you inherently right-wing. It makes you an authoritarian.