The Schottky electron source is predominant in today's focused electron-beam equipment, but its properties are still not fully understood. Generally, its performance is predicted, assuming its tip end geometry is known and stable. In this work, it is shown that the size of the end facet (slowly) shrinks upon reduction in the extraction voltage and (more rapidly) grows upon restoration of the original voltage. Furthermore, the shape of the end facet could be made to change from more circular to octagonal or more squarish. These changes affect the properties of the beamlet that will be cut from the facet beam for practical applications. Better knowledge of the in situ shape of the emitter allows for a better prediction of its performance and stability.