I am replacing my bathtub with a walk-in shower and I need to raise the shower valve. I am a novice when dealing with plumbing... is this job that difficult or should I call in a pro?
While soldering isn't all that hard, considering that this is going to be hidden behind a wall, and you haven't done it before, you might want to have this done. Once the demolition is done, access is easy, and it shouldn't take that much time (therefore money).
Keep in mind, though, that you'll probably need to upgrade the drain as well to 2" (it's probably 1.5" now), and most people prefer to have the drain centered in the showerpan...so, unless you've got an unusual tub, that will have to be moved as well. This may mean tearing up the subfloor, or the ceiling below (or slab).
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013