Shiva Purana
तथापि यजमानस्य यज्ञस्य च सहर्त्विजः ॥ सद्य एव शिरश्छेदस्साधु संपद्यते फलम् ॥ ६४ ॥
Nevertheless, the priests were present with the performer of the sacrifice. The head is immediately cut off and the results are good.
english translation
tathApi yajamAnasya yajJasya ca sahartvijaH ॥ sadya eva zirazchedassAdhu saMpadyate phalam ॥ 64 ॥
hk transliteration by Sanscript