Blizzard solved this problem in WoW, actually. Transmogrification. It was added when Patch 4.3 was released (during the Cataclysm expansion, so around 2010-2011). Basically, you're able to go to a transmog vendor to change the appearance of your gear to gear that you've already picked up. There's an appearance tab that keeps track of any gear that you've picked up and able able to be transmogrified. There are a few restrictions, but mostly any piece of gear can be transmogrified. it's also where you go to hide your armor.
For example, let's say you picked up a really super cool looking jacket a while ago and you love it and never wanna part with it, but you just finished a quest and got rewarded with a jacket that looks hideous, but it has better stats. Just go to the transmog vendor, select the item you want to transmog and the item you want to transmog it to, pay a small fee and boom! You got your awesome-looking jacket with the upgraded stats!
Here's a link to the transmog page on the wiki if anyone wants to read more about it:
https://wow.gamepedia.com/Transmogrification
Now, lore-wise, I think this could work. Sure, it came from a fantasy world, but in this world, the technology is very advanced. If someone from one of the big corporations were to make some sort of device that could do this, I think it would fit right in.
Or maybe the person who made it isn't from one of the corporations, but the corporations got wind of it and set out to get the device for their own purposes, and you were hired (or decided on your own) to either get the device or save the person from the corporation's security forces. You could develop a whole subplot around unlocking this feature! Or it could just be a feature, either works.
What do you guys think?