Matsya Purana — Uma’s Austerities and the Slaying of the Deceiver Asura ĀḌi
इत्युक्तो दैत्यसिंहस्तु प्रोवाचाम्बुजसंभवम् रूपस्य परिवर्तो मे यदा स्यात्पद्मसंभव //
ityukto daityasiṃhastu provācāmbujasaṃbhavam rūpasya parivarto me yadā syātpadmasaṃbhava //
Thus addressed, the lion among the Daityas spoke to the Lotus-born (Brahmā): “O Padma-born, when will the transformation of my form take place?”
इति (thus); उक्तः (having been spoken to/addressed); दैत्यसिंहः (the lion among Daityas, i.e., a foremost Daitya); तु (indeed/then); प्रोवाच (said/spoke); अम्बुजसंभवम् (to the Lotus-born, Brahmā); रूपस्य (of the form); परिवर्तनः (change/transformation); मे (of me/mine); यदा (when); स्यात् (may be/shall be); पद्मसंभव (O Lotus-born, Brahmā)
It does not describe Pralaya directly; it reflects a Puranic cosmological setting where beings petition Brahmā about changes in form, a theme tied to creation, re-creation, and divine ordinances.
Indirectly, it highlights the ethic of approaching legitimate authority for clarification—analogous to kings and householders seeking guidance from dharma-teachers or elders before major actions.
No explicit Vāstu or ritual procedure is stated; the verse is a dialogue line about a boon-like transformation, not temple-building or consecration rules.