you can find models on the internet, just look for apostasy letter.
Do not need to be to the bishop, any priest can do it, but he needs to find your baptism register first...

@Pedrohbds I got that, thanks.

they won't erase it because it happened, but they can register that you renounced it and you are not a member anymore.
Actually for any religion, an apostate is a lot worse than a non initiated XD.
The official way to deal with apostates is to insulate them from the community, Mormons do it very well to the point of families ignoring their children. But Catholics are not that powerful anymore

@Pedrohbds They used to be grilled at the stake.

@PontifexMarximus No, Apostates should not be killed, just excluded, they were burned because an insulated person would eventually be accused of satanism or witchcraft, then burned or die of hunger, cold or accused by a common crime as in a high collective society as medieval Europe, was not possible to live alone without magic powers from the devil.

And make no mistake, a pope cannot be wrong by definition, meaning to say that once a pope write a document, it cannot be changed, even by another pope.
SO... Yes the manual to identify, hunt and punish witches are still valid AND it is not applied because local secular armies are more powerful than the catholic armies nowadays.

The catholic church asked forgiveness by the errors, failures rushes, political interests etc during the inquisition, but they never changed the doctrine (Catholics are masters on this, they say that they applied the doctrine wrongly, but they never change the doctrine, including the new pope). The inquisition still exists, the previous pope was the leader of it. They just don't have the power they had before.

@Pedrohbds Of course they shouldn't … luckily times have changed... Many more people now opt to not have their children baptised. I was still baptised, but I didn't have my children baptised.

Better not to join an evil organisation in the first place then there is no need to distance oneself from it.

@PontifexMarximus It was not my opinion there, it was the canonical law. I am against death penalty in any case (except for rare cases of massive civil unrest to the point that the prisional system collapses, like wars or massive rebellions, basically when its a case of survival of the state)
In the Catholicism apostasy is not punishable by death, but by ostracism that in medieval times means death anyway.

@Pedrohbds Would that also apply to North Korea and Saudi Arabia?

@Pedrohbds In part of Europe apostasy was punishable by death un the 18th century according to several French historians.
[midilibre.fr]

@PontifexMarximus that is new for me, was it a church policy or policy of the French state?
Plus when I talk about a state I am immagining a modern state based on the principles oh human rights. Saudi Arabia and NK are not states, they are autocracies.

@Pedrohbds Unfortunately Saudi Arabia is even a founding member of the UNO and in September 2015, Faisal bin Hassan Trad, Saudi Arabia's ambassador to the UN in Geneva, was elected Chair of the UNHRC Advisory Committee.
North Korea has been a member of the UN since 1991.

Unfortunately there is only one selection criterion to qualify as a country: brut force.

@PontifexMarximus as I say, my definition, but of UN the definition is a lot larger, and it should be.
But talking about human rights (when discussion death penalty) on a state that has no human rights is useless...

@Pedrohbds Of course … but the drama is that the most powerful players are not about to relinquish their power of deciding who can live and who has to die. We live in a very strange world indeed. Unfortunately far too many people are addicted to the idea of punishment.

more like a Vatican cleaner.

Excellent idea! And then frame it together with the baptism certificate. You give a me great idea.

What if you don't know what Catholic Church you were baptized in? Also, I was given last rights when I was an infant. I wonder if that would make a difference.

@kiramea you can look at your baptism certificate.
The hard part is to find your page in the book of baptism, if you know the church they can look in the books, if you have the certificate, the book and page are there.
But technically if you live in a country where you have free association right, you just need to ask to leave formally, they can't keep you connected to them against your will.
If you know at least the city it will be easy to find..
Technically any priest can (and need to) put you out for apostasy, so just go into any church in front of a priest with a document telling that you renounce the catholic faith and if he do not excommunicate/register the apostasy there he is risking being excommunicated himself.
But due to bureaucratic reasons you can still be counted as a member as it will be difficult to relate an apostate in one corner of the country with a baptized in the other corner.
And the priest can argue that he do not know if you are a baptized person to begin with, so he cannot register the apostasy...

@Pedrohbds I don't have my baptism certificate and both parents are deceased. Besides, if they really feel the need to count me, let them. It's not worth my time to track it down.

"excomongate". What a great word, but I think you made it up

Church taxes.

Some people feel it is something they can do to express their frustration. See my link above.

It's being hit on the head lessons in here.

Hereby I excommunicate you!

Allusion here was to Monty Python's Argument Clinic sketch: "I'd like to have an argument, please." Sketch also includes being hit on the head lessons.

Just being silly.
[vimeo.com]

Well, in Germany and Austria there is a church tax which you can only get out of by renouncing whatever faith you were "born into." It's quite possible that there is a similar motive in France although as a rule they are much better about separation of church and state.

Also, if atheists don't self-identify explicitly, they are counted as default Christians for statistical purposes, which perpetuates Christian power and atheists' and others' sense of marginalization

I get this image of big fluffy towels.

It took me years to get off the rolls of the Mormon church -- and I'm still not 100% sure I made it. If they put as much effort into actual good work as they do keeping track of supposed members, the world would likely be a much better place.

@RichCC
I got an image of being dropped into the desert. I wonder where I am in the Mormon records... Do they write you off after a few decades of silence?

@Holysocks

I'm not sure how they do their records or whether I would qualify as a typical case. The last true link I had to the LDS church was Cub Scouts over 40 years ago. I stayed out of Boy Scouts because by that time I realized they they ran that whole show in our small town. Ugh.

But my mother was a serious member. She even taught genealogy at their temple in Mesa. I have no way of telling what part she might have played in the interactions over time. I know I am in her records. She is my biological mother after all.
I don't even know how much she would need to have been involved. Some 'well meaning' church members could have accessed her lineage without her knowledge for all I know.
At this point, my parents are gone and I've stopped worrying about it. Even if I was concerned about feedback she might have gotten from inside the church, that's gone now.

I will say I haven't been contacted in several years (fingers crossed. Can you tell I don't have a supernatural bone in my body -- ha, ha.) -- not even door-to-door. But my current house is a bit off the street.
I haven't had any trick-or-treaters in about the same time. I figure folks have decided it's not worth the effort. (We just make sure to get candy we like and eat it after the fact.)

[ffrf.org]

Steven Colbert did a skit on this, using a hair dryer as a way to unbaptize people. It was fricking funny, but hard to find now (it was many years ago).