FRH[exp_] corresponds to
FixedPoint[ReleaseHold, exp], i.e. FRH removes
all HoldForm and Hold in exp.
Notice that FRH will not be able to reinsert
abbreviations if they were introduced by Collect2 running
in parallel mode. For that you need to use FRH2
Overview, Collect2, FRH2, Isolate.
Hold[1 - 1 - Hold[2 - 2]]\text{Hold}[-\text{Hold}[2-2]+1-1]
FRH[%]0
Isolate[ToRadicals[Solve[x^3 - x - 1 == 0]], x, IsolateNames -> KK]\{\{x\to \;\text{KK}(21)\},\{x\to \;\text{KK}(24)\},\{x\to \;\text{KK}(25)\}\}
FRH[%]\left\{\left\{x\to \frac{1}{3} \sqrt[3]{\frac{27}{2}-\frac{3 \sqrt{69}}{2}}+\frac{\sqrt[3]{\frac{1}{2} \left(9+\sqrt{69}\right)}}{3^{2/3}}\right\},\left\{x\to -\frac{1}{6} \left(1-i \sqrt{3}\right) \sqrt[3]{\frac{27}{2}-\frac{3 \sqrt{69}}{2}}-\frac{\left(1+i \sqrt{3}\right) \sqrt[3]{\frac{1}{2} \left(9+\sqrt{69}\right)}}{2\ 3^{2/3}}\right\},\left\{x\to -\frac{1}{6} \left(1+i \sqrt{3}\right) \sqrt[3]{\frac{27}{2}-\frac{3 \sqrt{69}}{2}}-\frac{\left(1-i \sqrt{3}\right) \sqrt[3]{\frac{1}{2} \left(9+\sqrt{69}\right)}}{2\ 3^{2/3}}\right\}\right\}