I would just give it time. Most finishes take about three weeks to fully cure. During the initial phase the carriers off-gas (flash off), then the polymerization starts while the rest slowly leave. You do not say whether this was water-borne (glycol-ether) or oil-based (mineral spirits). While different smells, the water-borne usually works a little faster.
Just reading the title, I was speculating that someone polyurethaned the inside of a cabinet -- that smell can linger for a LONG time.