The platinum jubilee of Elizabeth II has naturally revived debate over whether the UK should abolish its monarchy. I see three options:

1. Add an elected President for a semi-presidential or similar system;
2. Abolish the PM for a presidential system;
3. Fold the Head of State position into the existing post of PM, which is still appointed or lost through Parliament.

There are [many historical examples](https://en.wikipedia.org/wiki/List_of_countries_by_date_of_transition_to_republican_system_of_government) of 1/2. (I'm not sure 3 has happened; as best I can tell, a PM only exists with someone else Head of State.)

To make the title question more precise:

**Are there historical examples of 1-3 among nations that were already democracies and constitutional monarchies, and dissolved a monarchy that was uniquely or centrally theirs?**

The last clause excludes cases such as Barbados opting out of the UK monarchy. All criteria serve to exclude historical motives not relevant to the UK in 2022.