APEX ¹²CO(2–1) spectra of three observed galaxies in different quenching phases. Top row panels: spectra for each galaxy in green, where the dotted line represents the observation σ_RMS. Top row panel: titles, the name of the galaxy (as in the CALIFA database) and its morphology, CO signal-to-noise ratio (S/N), and the logarithmic ratio of the galaxy global SFR to the global star formation main sequence (ΔSFMS_g). Middle row panels: continuum RGB images extracted from the CALIFA data cubes using u- (blue), g- (green) and r- (red) bands. Bottom row: W_Hα maps are displayed in diverging red colours where W_Hα < 6 Å, while the diverging blue ones illustrate the part of the map where W_Hα > 6 Å. The colour maps are centred at W_Hα = 6 Å in logarithmic units, and this value is indicated as a black vertical line in the colour bars. Black contours mark the 25, 50, and 75 percentiles of the log(F_Hα) distribution,previously masked at 3σ_RMS. The W_{H α} map is also masked below 3σ_RMS of the Hα flux map. In panel legends, the median Hα equivalent width across the whole map (⟨W_Hα,g⟩) and within the beam aperture (⟨W_Hα,b⟩) are presented. In the panels of the two bottom rows, the green circle shows the APEX beam (FWHM = 26.2 arcsec at 230 GHz), while white ellipsoids indicate 1 and 2 R_eff.