VEVOR Automatic Electric Wire Stripping Machine 0.05"-0.98", Cable Wire Stripping Machine, Portable Wire Stripper Machine for Scrap Copper Recycling, Including A Extra Blade(Blue)

I found loosing both nuts while still in position, then remove from the holding slot grab one nut and tap against a hard service and blade should pop out of placing making it easier to re-insert new blade into place.

You can replace it by simply unscrewing the screw.