As a noun or as a name, please be specific; as for each there are several different ways. If you mean the 'palm healing' method, it's originally written 靈氣 /rei ki/ but also written 霊気 with no difference, except the latter word is more commonly used meaning 'aura'.
Za Rei
グレイス /gu rei su/ is the Japanese equivalent of 'Grace' as a name.
The same way you write it - rei. Pronunciation RAY-ee.
Za-rei
レイチェル /rei che ru/ is the Japanese spelling of the name Rachael.
It is written デジレー /de ji rei/.
Both ドレイク /do rei ku/ and ドレーク /do ree ku/ exist as Japanese spellings of that name. The former seems slightly more commonly used.[ee = elongated 'e' sound]
If you mean transliteration of the word into Japanese, it would be グレイス /gu rei su/. Romanization of it would be 'gureisu'.
Its used as a name but the "Rei" in "Reiko" means ZERO.
names do not translate if you want to know how to write it ask:- how do i write "name" in japanese?
names do not translate if you want to know how to write it ask:- how do i write "name" in japanese?
Rei Chao's birth name is Gonzalo Rei Chao.