I don’t think they can, the way things stand.
They attempted to pass House Bill 2720 to allow exactly this, and it died in committee on May 24 2021.https://lawandcrime.com/politics/arizona-gop-bill-would-allow-gop-controlled-state-legislature-to-overturn-presidential-popular-vote/
They are going back into session on September 24th or whatever, I assume…. Otherwise I’m not sure what Wendy Rogers would be reading out on the “floor,” or to whom.
So essentially they need to introduce and pass similar legislation before they could decertify, since HB2720 would not be necessary , and Joe Biden wouldn’t have been screaming about it, if they already had this power.
That is not to say they can’t or won’t immediately pass a similar bill now.
But they didn’t.
And the answer is, right now, no, they cannot decertify it even if Biden goes on national television and says he stole the election.