Whatever reason you'd like to tie up a wet or dry version of a fly pattern, it's pretty easy to do at the fly tying vise. It's easier to do with simple patterns, but almost any one can be altered. In fact, this used to be a pretty common practice among fly tiers back in the day - just read a little in Ray Bergman's book Trout, & you'll see what I mean.
Without going into too much detail - because we don't need to as it's pretty easy - here's a quick method of tying a different version of a fly pattern. In our example here we'll take a wet fly & tie it up as a dry, so we're taking the pattern from wet to dry:
-Hook: use a standard dry fly hook in the proper size (obviously)
-Body: this you keep the same as the wet fly pattern - same materials, proportions, colors, etc.
-Hackle: use the same color as what the wet fly pattern called for, but but use a dry fly, or rooster, hackle in the proper size, one with good, stiff barbs.
-Wings: these can be optional as not all dry flies need wings, but most anglers like to have wings on their dries. Often I'll use wings made from divided calf hair, usually in white as it's highly visible.
-Tails: these, too are optional especially if you leave the wings off, otherwise a stiff clump of feathers in the proper color will work well.
It goes without saying that if you needed to go from a dry fly pattern to a wet, you'd simply reverse this process. For example, you might use a duck flank feather for the wing, dyed in the proper color.
I often like to carry a wet version of some dry flies, especially on heavy hatches. My logic is that if there are so many bugs on the water that my fly isn't getting noticed by the trout, maybe a cripple will look like an easier meal to them. I'm not sure how true this actually is, but it's a theory I go by.
Switching up fly patterns is quick & easy. Give it a shot to add some versatility to your favorite wet or dry patterns.