Seams and roof openings
A membrane seam, puncture or flashing at a curb can admit water into the layers below. The surface must be prepared for the compatible patch, weld or detail repair, with the surrounding material sound enough to accept it.
Rooftop equipment also has mechanical and electrical connections. Those trade needs are coordinated separately from the roof flashing.
Edges and attachment
Edge metal and perimeter details secure and terminate the roof. Loose or damaged sections affect the connection between the covering and the building. Repair needs to address attachment and flashing, rather than only the exposed edge.
The existing deck and the specified roof assembly determine what the attachment must connect to.
Drains and water movement
A blocked outlet, failed drain connection and low area in the roof are different issues. Cleaning one drain does not correct inadequate slope or wet insulation.
Water entering above the occupied space can travel within the roof assembly, so the interior drip location is a starting point for the investigation.