Lets say we have a line that goes through the origin, which we'll write as y = ax. If I have a point (x, y) and reflect it over the line y = ax, then what is the resulting point?

For example, when we reflect over x = 0, the outcome is (-x, y)

Or when we reflect over y = x, the outcome is (y, x)

So is there a general way of writing the reflected point over the line y = ax?