It is only necessary to lower the headliner. Only do those step in headliner replacement that will lower the headliner enough to gain access to the part. Refer to
Headlining Trim Panel Replacement
.
Disconnect the drain hose from the spigot, located in the rear corner of the sunroof module.
Remove the grommet from the rear drain hose valve.
Remove the drain hose through the large hole in the rear pillar.