To a certain degree you can alter the sound of Keylab presets. Just park it within multi-mode and scroll down to edit mode (which means using the rotary knobs and ADSR faders like on your hardware controller) and a number of effects which you can channel theough FX1 and FX2. Think of stuff like delay, fazer, stereo rotation, destroyer etc.
Unless you own a dedicated plug-in you can not fundamentally alter the sound. Like, if there's a preset with too much reverb (like the JP8 preset of Pizzicat) you can't get rid of that reverb within Analog Lab. You can or enrich a sound or make it weirder, but you can't strip it of its basic characteristics. You'll have to dig deeper then. That's my theory. Hope it helps somewhat?