Hello, everyone,
Sorry if I repeat what’s been said- Haven’t read the thread.
If you’re in a regular protestant church (meaning, not the LDS, Jehovah’s witnesses, Unitarians etc)- Basically you don’t deny the catholic teachings on the Blessed Trinity and Divinity of Christ etc- These are basic in all Christianity and denied only by fringe groups like the above examples. This is important because otherwise, your baptism would not be regarded as valid by the catholic Church. However, most Protestants are “good” on this issue in the eyes of the church, and virtually all baptisms involve water and the invocation of the Blessed Trinity, In the name of the Father and the Son and the Holy Spirit, so valid.
If you’re ok on that point, my understanding is that it’s possible to partake of the blessed sacrament provided:
a) You must express desire for the sacraments (obviously).
b) You must also express the faith of the church with regard to that sacrament- You must believe that it is the actual body and blood of our Lord Jesus Christ and not just symbolic.
c) You must go to confession beforehand, as a catholic does during first holy communion, or after committing a mortal sin. This is because we do not believe that a simple 'Jesus forgive me" of the heart guarantees cleansing of the soul for that sin if it’s mortal. Since protestants have no valid priesthood or confession, you must go to confession to a Catholic priest first, to avoid desecrating the sacrament/sacrilage.
Someone correct me if i’m wrong. But I believe that the Church allows individual members of protestant churches with valid faith (in a basic sense- Belief in Trinity, Jesus is God and man, was born of a virgin, crucified, died, resurrected, ascended will come again etc), and have been validly baptized with water and the name of the Blessed Trinity, can approach the church as individuals for the sacraments, if they satisfy the given requirements. I believe individual Orthodox can receive much easier because they have most requirements, short of being catholic, if they cannot access their own church for the same and the church is available to them.