Abstract: Stator blade counts of an upper compressor casing for adjacent stages S0 and S1 are changed in the field to provide additional stator vanes and hence an increased vane count. Particularly, the upper casing half of the compressor is removed from the lower casing half. The original stator vanes on opposite axial sides of the first stage buckets are removed from the upper casing half and replaced by an additional sets of stator vanes providing a non-uniform vane spacing as between the upper and lower halves of the compressor as well as between axially adjacent stages S0 and S1. The unequal vane counts reduce the vibratory response of the rotating blades between stages S0 and S1.