Call and say water is coming in now
An active leak puts the space below the roof first. Keep people away from sagging ceilings, water near electrical fittings and any area that looks unstable. If there is immediate danger, move to a safe place and contact emergency services. Do not climb onto wet or damaged roofing.
When you call, the useful details are simple: where water is showing, whether it is still coming in and whether roofing or a branch has fallen. The first roofing decision is whether safe protection can limit further entry while the opening is assessed.
The stain may not sit directly beneath the failed detail. Water can travel along wood or other layers before it drips into a room. A repair should follow that path back to the roof rather than cover only the area above the visible mark.