This is a short tutorial on how to save a plant that has suffered damage to its roots.
A plant is a balanced system. It has just enough roots to support its foliage.
If you need to transplant to a smaller container, root loss is inevitable.
If you want to avoid wilting and possibly the plant's death, the solution is simple.
Estimate your root loss(10%? 30%?) and remove a similar amount of foliage. In larger plants, remove entire branches to avoid having the plant try to replace the lost foliage. It's best to remove the lowest branches.
Doing this correctly will allow the remaining roots to support the remaining foliage without shocking the plant. The plant will often continue growing without a break. Even if there is some shock, the recovery will be much faster.
I've done this more times than I can count.
It works.
This is intended as an emergency method, used only when necessary.
Done correctly, with forethought, the loss will be minimal.
I hope you never have to use this, but in a pinch, it will cut your losses.