Reverse a conversion when using a Japanese input source on Mac
After you set up a Japanese input source, you can, in some apps, reverse a text conversion. To see if the app supports reversing text conversions, check the app’s documentation or contact the developer.
On your Mac, switch to a Japanese input source.
In an app, place the insertion point where you want to make the change or select a part of the word.
Click the Input menu in the menu bar, then choose Reverse Conversion.
Alternatively, you can press Control-Shift-R, or press the Kana key on a JIS keyboard twice.