Is there a formal process to legally leave Islam?

Question

For whatever reason, an ex-Muslim might desire to be legally recognized as a non-Muslim under sharia. A question on Quora asks about a specific case of this, where a Muslim woman wants to formally leave Islam to marry a non-Muslim man. In her specific case, an (unreferenced) answer by Jim Duley says:

Converting from Islam is not "impossible" but is not easy in Malaysia. If your wife were a Malay, she would have to get permission to convert from an Islamic court.

This suggests there is a formal process through an Islamic court in Malaysia. I want to know if this is correct, and if it applies more generally.

Question: Is there a formal process to legally leave Islam?

It seems like there should be a process, otherwise it could be difficult determining how sharia applies in some cases (e.g. inheritance, marriage). Note: while some countries have the death penalty for apostasy, other countries do not; see Apostasy in Islam, Wikipedia.

_{(...and before you ask, no I'm not leaving Islam.)}

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This question (Is there a formal process to legally leave Islam?) currently has two votes as a duplicate of Is punishment for leaving Islam death?. However, I don't see and mention of the (non-)existence of a formal process [whether or not it results in the death penalty (which is debated in the linked question)].

Answer 1

If the hadd punishment were applied (i.e., the death penalty), there is a process to follow, as described by IslamWeb:

It should be noted here that this punishment is carried out only by the Muslim authorities. So, no individual should give himself the right to act on behalf of the authorities.

The apostate is first told to repent and given three days to decide. If he confesses in front of the judge, who has the necessary authority to apply the death penalty, that he does not want to repent, then he is executed.

In the case of Malaysia (where the death penalty is not applied for apostasy), it appears there is no formal legal process.

News articles such as Muslim Man Has Right to Leave Islam for Christianity, Malaysian High Court Rules (ChristianPost.com, 2016) and Former Muslim Women in Malaysia Lose Appeal to Leave Islam - Here's What Happens Next (CBNNews.com, 2018) show that such cases are going through courts in Malaysia.

This would not happen if there is a formal process to legally leave Islam.