Abstract: A pet access door apparatus for an associated building includes a frame; a first opening defined by the frame having a first size; a second opening defined by the frame having a second size that is different from the first size. The openings each have a flap disposed therein, each a flap has an edge. The edge engages the frame whereby the flap is suspended from the edge. Each flap has first and second sides. The apparatus further includes discrete first retractable stops abutting a first side of each of the flaps, each first retractable stop retracts to allow movement of the abutting flap in a first direction and extends to prevent movement of the abutting flap in the first direction; the apparatus further includes discrete second stops abutting a second side of each of the flaps, each second stop retracts to allow movement of the second flap in a second direction and extends to prevent movement of the second flap in the second direction.