Anton had plenty of experience influencing the soul and magic by adjusting memories.
At first, he had used the Memory Charm to alter the memories of Tom's Remains, making them utterly pure and thereby unleashing a powerful Tickling Charm. The results had been amazing—even Dumbledore had fallen victim to it. (Chapter 182)
Later, as Anton gained a deeper understanding of the Six Elements of the Soul and the Soul Black Line, he found an even better method than the Memory Charm.
If a person's memories could be taken out of their head and stored in a Pensieve, did that mean we could dress them up all fancy and then put them back in?
The answer was yes.
Anton had tried this experiment on a Dark Wizard who'd planned to frame him. The results had been fantastic. (Chapter 771)
"This is really about understanding different levels of memory."
Anton happily explained the distinction to Dumbledore. "The Memory Charm doesn't actually change memories at all. That's why people have such a hard time noticing when they've been hit with it."
Today, Anton and Dumbledore had come to see Fudge and have him lead them to Barty Crouch Jr., who was being held in the prison.
Scrimgeour from the Auror Office was there as well. He'd clearly been told what the two great wizards intended to do, and had withdrawn all the Aurors stationed around the cell.
"Oh?" Anton looked around the cell curiously. "I've stayed here before. This is the very cell I was held in before being sent to Azkaban."
He even looked rather nostalgic as he said it, which left Fudge and Scrimgeour wearing strange expressions.
Dumbledore ignored Anton's occasional oddities and asked curiously, "The Memory Charm can't change memories?"
It was clearly a novel idea. Even Fudge and Scrimgeour