Can I send in an improved ACT score instead of a SAT score that I sent in, past their deadline?

I am a senior and I applied for UW and 4 other UC schools with either a superscored SAT or (for the UC schools) just my june SAT. However I retook my December ACT this month and got my score back. My ACT score is slightly better than my SAT score when translated and I would rather send this in to most of my colleges. Would I be able to update my score I’ve already sent to past colleges, instead of the SAT I sent, even if I am way past the application deadline? I also only got my multiple choice score for my ACT back already and I don’t know if the Essay score will come in time (hopefully) to send to colleges that are due on January 1st?

Sorry if this seemed very messy but all my attempts to find answers online have failed and I am nervous if I were to contact my admissions counselors for those schools that I would sound stupid.

The worst that can happen is that they ignore the score and the fee is waisted.

UC’s SAT/ACT score deadline is December 31. If scores are received after that deadline, there is no guarantee that they will be considered in your application review. That said, you have nothing to lose if you update your UC application with new ACT score and send it to the campuses you applied.