Catalyzes the hydrolyze of the acetyl group at the sn-2 position of platelet-activating factor (PAF) and its analogs, leading to their inactivation (PubMed:9494101). Hydrolyzes propionyl and butyroyl moieties approximately half as effectively as PAF (By similarity). Also catalyzes transacetylation of the acetyl group from platelet-activating factor (PAF) to lysoplasmalogen and to sphingosine, producing plasmalogen analogs of PAF and N-acetylsphingosine (C2- ceramide) respectively. Has a marked selectivity for phospholipids with short acyl chains at the sn-2 position (By similarity). {ECO:0000250|UniProtKB:P79106, ECO:0000250|UniProtKB:P83006, ECO:0000269|PubMed:9494101}. This is the function of ENSG00000158006 (PAFAH2, platelet activating factor acetylhydrolase 2).