How do you turn XP 200 permanent hair color into a semi permanent hair color?

You cannot turn a permanent hair colour into a semi permanent hair colour. Permanent colours are made of small colour molecules that need a developer to create the chemical reaction required for the colour molecules to penetrate the hair shaft and tint to the desired shade.

True Semi permanents are pretty much topical with mainly large colour molecules. (which is why you see the shade while the product is still in its original packaging) They require no developer as they sit ON TOP of the hair shaft with fewer smaller colour molecules that penetrate the cuticle.