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 involves changes in cell morphology and altered gene expression patterns. For example, Candida albicans switches 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
Mating type switching is not considered a type of phenotypic switching: for mating type switching, consider instead annotating to 'mating type switching ; GO:0007533'.