Hi
PreviousStepName = ...
UnpivotedOtherColumns = Table.UnpivotOtherColumns(PreviousStepName, {"Person"}, "Attribute", "Value"),
FilteredValues = Table.SelectRows(UnpivotedOtherColumns, each ([Value] = 1)),
GroupedRows = Table.Group(FilteredValues, {"Person"},
{{"Attributes", each Text.Combine([Attribute],", "), type text}}
)