With regards to music pedagogical activities and species counterpoint, it refers to a more specific set of patterns.
[1] It is not to be confused with changing tones, which resolve to the original note.
note de rechange) all of which relate to the concepts of "change" or "exchange".
This means there are only three possible essential dissonant cambiatas in third species: Two above the cantus firmus, with vertical intervals 8-7-5-6 (Ex.1) and 6-b5-3-4 (Ex.2); and one below the C.F., with 3-4-6-5 (Ex.3).
The consonant cambiata is not considered an idiom like the dissonant version as it does not break any rules of species counterpoint by itself.
Rhythmically, it is only essential that the dissonance that is skipped from be in a weak position, when not considering any other rules which may apply.