transform themselves into a believable mother/daughter pair 
(ROOT (S (VP (VB transform) (NP (PRP themselves)) (PP (IN into) (NP (DT a) (JJ believable) (NML (NN mother) (, /) (NN daughter)) (NN pair))))))
(ROOT (S (VP (VB ) (NP (PRP )) (PP (IN ) (NP (DT ) (JJ ) (NML (NN ) (, ) (NN )) (NN ))))))