Noon Saakin & Tanween Rules
Iqlab (Conversion) إِقْلَاب
Convert the noon to a meem — when followed by ب.
When a noon saakin or tanween is followed by ba, the noon is converted into a hidden meem with a ghunnah of two counts. Visually the Mushaf marks this with a small meem (ࢽ) above the noon or in place of the tanween.
Quran examples
مِنۢ بَعْدِ
Noon + ba → iqlab. The small meem above the noon is the marker. · 2:27
سَمِيعۢ بَصِيرٌ
Tanween + ba → iqlab. · 17:1