A reversible switch of a cell from one cell type or form to another, at a frequency above the expected frequency for somatic mutations. Phenotypic switching begins with changes in cell morphology and altered gene expression patterns and ends when the morphology of a population of cells has reverted back to the default state, accompanied by altered expression patterns. For example, Candida albicans switches from a unicellular form to an invasive multicellular filamentous form upon infection of host tissue, and from white cells to opaque cells for sexual mating. Phenotypic switching also occurs in multicellular organisms; smooth muscle cells (SMCs) exhibit phenotypic transitions to allow rapid adaption to fluctuating environmental cues.