I think you all are missing something. All the effects have a mix control. You can accomplish the same thing as turning an effect on or off by setting the mix to zero in the base state and whatever other percentage in the morph state. This way you can morph somethings while simultaneously turning other things off by morphing for zero to 100 or zero to whatever.
so for example, you want the delay off in the base state, leave the delay block ON, but set the mix of the delay effect to Zero. Hit the morph button and set the mix of the delay to whatever you want it for the solo, say 45%.
You can effectively turn on or off any effect with way with morph using the mix control. Even better, I find it helpful that if I want a more prominent delay for part of a song, leaving just a little of it mixed in when I don’t sometimes makes the transition smoother, since I’m not complete bypassing the effect.
obviously, as others pointed out, you could just copy and paste the rig into another slot in the performance and tweak it different for that part. However I found it useful for a while to put all the sounds I need for a particular song in just one Rig when possible. Utilizing morph this way gives me two completely different combos if effects with just one button press. Often times I could fit four or five songs worth of Rig into a single performance. Given that I also use the ducking parameter set to about 1.0, I find I often don’t turn by delays on and off mid song as my playing style naturally takes care of it.