How do elves confirm the decision to be mortal?

Appreciate there are various elves/half-elves in the legendarium that choose to become mortal. I’ve always wondered— how do they go about notifying the relevant authorities that their soul is now on a different path? I appreciate some of them have some engagement with various Valar and Maiar, but others (like Arwen) don’t appear to— do we know anything about the logistics here?