Some Brothers have a hole in the back of the machine, behind the needle bar. You'll need a flashlight to see what kind of tool to use (screwdriver, torx or hex). Insert the tool and turn. Watch which direction the needle moves and turn accordingly.
Some Brothers don't have a metal frame, so the machine can actually twist and throw off the needle/hook distance. There are no adjustments on those particular machines. So, if it doesn't have the adjustment hole in the back, it's disposable.