Cartoon illustrating the scenario that is tested in this work. On the top, a full disk is shown, leading to an observed spectrum with bright H₂O lines (illustrated in blue) and a relatively weaker 15 µm CO₂ feature (illustrated in green). On the bottom, a disk with a small inner cavity is illustrated. This could, for example, be carved by a companion. The cavity extends beyond the H₂O snowline but not beyond the CO₂ snowline, leading to an observed spectrum that shows a bright CO₂ feature and relatively weak H₂O lines. The values given for the locations of the H₂O and CO₂ snowlines are the midplane snowline locations of our fiducial, L_* = 1.4 L_⊙ full disk model based on AS 209.