Śatapatha Brāhmaṇa ("of a hundred paths") 3.9.2.8

3.9.2.8

sa yasyāgṛhītā abhyastamiyāt | tatra prāyaścittiḥ kriyate yadi purejānaḥ syānnināhyādgṛhṇīyāddivā hi tasya tāḥ purā gṛhītā bhavanti yadyu anījānaḥ syādya enamījāna upāvasito vā paryavasito vā syāttasya nināhyādgṛhṇīyāddivā hi tasya tāḥ purā gṛhītā bhavanti

And if the sun were to set on any one's (Vasatîvarîs) not having been taken, then expiation is made. If he have performed a (Soma-)sacrifice before this, let him (the Adhvaryu) take it from his tank, since that (water) of his has been taken before (sunset) by day. But should he not have offered before, if there be one who has offered (Soma) settled close by or somewhere thereabout, let him take it from his tank, since that (water) of his has been taken before, by day.