A method for assembling a stator stage of a gas turbine engine and an adjustment pin to perform the assembly method to lock a vane segment in a central section of the stator stage. The method includes inserting an adjustment pin into a through hole wherein the adjustment pin includes two end sections, inserting at least one wall segment of the vane segment into a slot of a central section, rotating the adjustment pin so that the central section is correctly positioned in the stator stage, deforming a deformable part of the adjustment pin so that the now deformed part establishes a force fit with at least one segment of a corresponding structure of the central section and thereby locking the adjustment pin and thus the central section in a fixed position in the stator stage.