مَالِكِ يَوْمِ الدِّينِ إِيَّاكَ نَعْبُدُ وَإِيَّاكَ نَسْتَعِينُ
Master of the Day of Recompense; You alone we worship and You alone we ask for help.
God is first described in the third person through attributes of praise. «إِيَّاكَ» turns to direct address. The movement takes the reciter from describing divine majesty to direct devotion and supplication.
This is the classic third-person → second-person shift. The fronting of «إِيَّاكَ» separately creates restriction or exclusivity; the change of grammatical address is iltifāt. These two rhetorical functions should not be conflated.