Adding to what Gigi said, I find that if I keep the blade active, I'm more careful because I know that shaving off could badly affect my sewing.
But if you really insist, most blades can be deactivated. There should be a lever or knob that you can push on. That will move the blade to the right enough to then rotate it out of the way. On my serger, I push a circular knob to the right and then rotate the knob towards me.