We study the evolutionary path of the Fornax cluster galaxy NGC$~$1436, whichis known to be currently transitioning from a spiral into a lenticularmorphology. This galaxy hosts an inner star-forming disc and an outer quiescentdisc, and we analyse data from the MeerKAT Fornax Survey, ALMA, and theFornax3D survey to study the interstellar medium and the stellar populations ofboth disc components. Thanks to the combination of high resolution andsensitivity of the MeerKAT data, we find that the$\textrm{H}\scriptstyle\mathrm{I}$ is entirely confined within the innerstar-forming disc, and that its kinematics is coincident with that of the CO.The cold gas disc is now well settled, which suggests that the galaxy has notbeen affected by any environmental interactions in the last $\sim1~$Gyr. Thestar formation history derived from the Fornax3D data shows that both the innerand outer disc experienced a burst of star formation $\sim5$ Gyr ago, followedby rapid quenching in the outer disc and by slow quenching in the inner disc,which continues forming stars to this day. We claim that NGC$~$1436 has begunto effectively interact with the cluster environment 5$~$Gyr ago, when acombination of gravitational and hydrodynamical interactions caused thetemporary enhancement of the star-formation rate. Furthermore, due to theweaker gravitational binding $\textrm{H}\scriptstyle\mathrm{I}$ was strippedfrom the outer disc, causing its rapid quenching. At the same time, accretionof gas onto the inner disc stopped, causing slow quenching in this region.