Both LAH and NaBH
4 don't reduce olefins(even if present in conjugation). But there is one exception found in reduction of

- aryl-

,

unsaturated compounds. With LAH, the double bond is also reduced along with the carbonyl. But still, NaBH
4 doesn't reduce the double bond and reduces only the carbonyl.
NaBH4, Xs, LAH
PhCH=CHCH2OH <----------------- PhCH=CHCHO ------------->PhCH2CH2CH2OH
or LAH, -10oC ether,350C