$sourceterm = $mytermstore.GetTerm("66c67639-db8a-4101-8778-afbf10bef644");
$tset = $mytermstore.GetTermSet("186fcb82-4aea-4a79-b2dd-77b3895b533b")
$reusedTerm = $tset.ReuseTerm($sourceterm, $False)
$mytermstore.CommitAll()

$sourceterm = $mytermstore.GetTerm("66c67639-db8a-4101-8778-afbf10bef644");
$parentTerm = $mytermstore.GetTerm("186fcb82-4aea-4a79-b2dd-blah")
$reusedTerm = $parentTerm.ReuseTerm($sourceterm, $False)
$mytermstore.CommitAll()