You’d have to federate the change out to other servers, editing the original author to be the new account. You’d need all the different activitypub platforms to support this otherwise different sites would show different info.

And it needs to originate from the original server as you couldn’t trust a new server claiming it’s you.

I’d guess it’s doable within a single platform, but federating out to other platforms seems tricky. That’s probably good enough though you’d need it to fail gracefully in situations it doesn’t work.