Are "writes to PPS or PLL registers" to be considered like Flash write? I.e. can they "out (DarioG)

I always had that doubt, but recently I needed to change the above (PPS and possibly PLL) at run time so I juat wanted to be sure... I suppose the answer is "no" but I just would want to avoid nasty surprises TIA PS: I am talking PIC24 and dsPIC but the q..