When the voting booths are to be erected, {HEAD ~ the retaining clips} are released to separate {TAIL ~ the two base members} 
When the voting booths are to be erected , { HEAD ~ the retaining clips } are released to separate { TAIL ~ the two base members }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL