Optical changing-look Active Galactic Nuclei ( AGN ) are a class of sources that change type within a short timescale of years or decades .
This change is characterised by the appearance or disappearance of broad emission lines , often associated with dramatic AGN continuum flux changes that are orders of magnitude larger than those expected from typical AGN variability .
In this work we study for the first time the host galaxy of a changing-look AGN , Mrk 590 , using high spatial resolution optical and near-infrared observations .
We discover that after \sim 10 yr absence , the optical broad emission lines of Mrk 590 have reappeared .
The AGN optical continuum flux however , is still \sim 10 times lower than that observed during the most luminous state in the 1990s .
The host galaxy shows a 4.5 kpc radius star-forming ring with knots of ionised and cold molecular gas emission .
Extended ionised and warm molecular gas emission are detected in the nucleus , indicating that there is a reservoir of gas as close as 60 pc from the black hole .
We observe a nuclear gas spiral between radii r \sim 0.5 - 2 kpc , which has been suggested as a dynamical mechanism able to drive the necessary gas to fuel AGN .
We also discover blue-shifted and high velocity dispersion [ O III ] emission out to a radius of 1 kpc , tracing a nuclear gas outflow .
The gas dynamics in Mrk 590 suggest a complex balance between gas inflow and outflow in the nucleus of the galaxy .