Yoga Sutras of Patanjali · 3.38

बन्धकारणशैथिल्यात्प्रचारसंवेदनाच्च चित्तस्य परशरीरावेशः॥३८॥

bandhakāraṇa-śaithilyāt pracāra-saṁvedanāc ca cittasya paraśarīrāveśaḥ

By the loosening of the causes of bondage and by knowledge of the passages, the mind of the yogi can enter another body.

— Yoga Sutras of Patanjali 3.38

Source: Sanskrit attributed to Patanjali (c. 2nd century BCE – 4th century CE). Public-domain English readings drawn from Swami Vivekananda's 'Raja Yoga' (1896) and Charles Johnston's 'The Yoga Sutras of Patanjali' (1912).