that is a ii half-diminshed 7th chord, (fmin7b5) in first inversion [as somebody before me correctly identified i think]. the g in the soprano is a non-chord tone (a retardation) to the a flat.
if i remember correctly, that was on "for us, and now...". for us being the V chord (Bb7), then the passing chord which would normally be V42 (Bb7 chord in 3rd inversion)... but instead of playing some variation of a chord spelled Bb D F Ab, she substituted it with the similar F Ab B D (three common tones). then to and now she played that III chord (Gm7).
a very nice passing chord; she coulda dropped that Eb to make it a fully diminished chord, but keeping the Eb maximized the amount of common tones between the three chords, making for a nice refreshing sound. i definitely stole that chord for myself! lol