power cord directionality

IF power cords do indeed have preferred directionality, and one is inadvertently flipped for a few hours, does it "harm"it?

Would not this equal to forcefully switch it's "gender"?

Who knows.  Try it and see if you must. 

Perhaps I was less than clear. This is umbilical cord btwn power supply and preamp. Carries DC I’m pretty sure. Neutrik
male and female ends. Was assembled backwards

Not the only thing that's backwards, apparently.

Power cords and fuses and any cables, even digital cables and HDMI cables, are directional in DC and AC circuits. Everybody is on board the DC train. It’s the AC train 🚂 that gives audiophiles a case of the 🍑 It’s because of the inherent directionality of wire. 🔜