Śatapatha Brāhmaṇa ("of a hundred paths") 8.6.3.13

8.6.3.13

yadveva punaścitimupadadhāti | etadvā etadayathāyathaṃ karoti yadāhavanīyādgārhapatyamuttaraṃ cinoti tadyatpunaścitimupadadhāti ya evāyamagniścitastamevaitadāhṛtyāsyopariṣṭātpunaścinoti tadyaccitaṃ santam punaścinoti tasmātpunaścitiḥ

And as to why he lays down the Punaskiti. Now, in laying down the Gârhapatya (hearth) upon the Âhavanîya, he surely does what is improper; but when he lays down the Punaskiti he thereby brings this Agni (or altar) that has been built, and builds it up again thereon; and because he again (punas) builds up (ki) that (Agni) already built, therefore (this is called) Punaskiti.