وَإِذَا دَخَلَ الْمُسَافِرُ مِصْرَهُ: أَتَمَّ الصَّلَاةَ وَإِنْ لَمْ يَنْوِ الْإِقَامَةَ فِيهِ.
Translation: When a traveller enters his own home town, he performs the full prayer even without making a new residence intention.
Returning to one’s established permanent home does not require a fresh fifteen-day intention.