Assimilation of manner of articulation: is much less noticeable, and it is only found in the most rapid and casual speech.
generally speaking, the tendency is again for regressive assimilation and the change in manner is most likely to be towards an “ easier” consonant, one which makes less obstruction to the air-passage.
It is thus possible to find cases where a final plosive becomes a fricative or nasal. Example: that side [ðæs saɪd ]; good night [ gʊn naɪ ].
But most unlikely that a final fricative or nasal would become a plosive. In one particular case, we find progressive assimilation of manner when a word-initial [ ð ] follows a plosive or nasal at the end of a preceding word, it is very common to find that the initial consonant becomes identical in manner to the final consonant but with dental place of articulation.
Example: in the [ɪn nə ]; get them [ get təm ]; read these [ riːd diː]. It seems that the [ð] frequently occurs with no discernable friction noise.