The two participles are very similar, so compare them directly.
MeaningForm
one who transforms / conjugatesمُصَرِّفٌ
that which is transformedمُصَرَّفٌ
The middle vowel is the key: مُصَرِّفٌ is active; مُصَرَّفٌ is passive.
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Ism Fa'il and Ism Maf'ool
Derived Trilateral (without Hamzah) - Bab 2: Taf'eel (Tasreef)
The two participles are very similar, so compare them directly.
MeaningForm
one who transforms / conjugatesمُصَرِّفٌ
that which is transformedمُصَرَّفٌ
The middle vowel is the key: مُصَرِّفٌ is active; مُصَرَّفٌ is passive.