This just came up in a Saturday casual play match and we had a lengthy debate about this:

If a player rolls three attack dice and uses Accuracy Corrector to cancel the results and add two hits can Palpatine be used to change the last cancelled dice to a hit/crit so there is a total of three hits?

My understanding was that Accuracy Corrector says the dice cannot be modified again, but others argued that Palpatine can change any single result once per round.

Palpatine is indeed a dice modification, and Accuracy Corrector says you can't modify your dice after adding two [boom] results. As the Rules Reference explains, "cannot" trumps other language.

So Palpatine isn't allowed to help once Accuracy Corrector is used on an attack.

Accuracy Corrector's results can NOT be modified. Furthermore, the cancelled result are GONE so there would be nothing for Palpatine to do there.

Palpatine simply cannot modify a canceled die. It would be interesting to hear the justification for thinking he could.

I suppose you could palp one of the pre-AC hits, but it would get cancelled when you triggered AC. If you rolled a pair of hits, then palped the third I don't know why you'd trigger AC anyway.

Cannot > Can