Can recommenders alter and resubmit their recommendations?

Title, basically. One of my extra recommenders, who has already submitted their letter, said they would like to update with some more information. Is that possible without completely removing them from the common app?

I think they can do anything they want including withdrawal of the recommendations. They don’t have to do through CA if they know where their recs went to.

Why do you ask this question?

One of my recommenders would like to add additional information to their previously submitted letter.