This only applies when the homophone is spoken or part of an audible phrase, so written text is safe.

It doesn’t change reality, just how people interpret something said aloud. You could change “Bare hands” to be interpreted as “Bear hands,” for example, but the person wouldn’t suddenly grow bear hands.

You can only change the meaning of the homophones.

It’s not all or nothing. You can change how a phrase is interpreted for everyone, or:

• You can affect only a specific instance of a phrase - including all recordings of it, if you want - but you need to hear that instance - or a recording of it - to do so. If you hear it live, you can affect everyone else’s interpretation as it’s spoken.
• You can choose not to affect how it is perceived by people when they say it aloud, and only when they hear it.
• You can affect only the perception of particular people for a given phrase, but you must either be point at them (pictures work) or be able to refer to them with five or fewer words, at least one of which is a homophone. For example, “my aunt.” Note that if you do this, both interpretations of the homophone are affected, if relevant, (e.g., “my ant”).
• You can make it so there’s a random chance (in 5% intervals, from 5% to 95%) that a phrase is misinterpreted.