1. To remove someone or something from some status, situation, mode, or role very gradually or in increments. In this usage, a noun or pronoun is used between "phase" and "out of." The board of directors agreed to phase the controversial CEO out of his position. The government announced that it will be phasing taxpayers out of the single-payer healthcare system over the next 12 months.

2. To disappear from some space or location by traveling another dimension or plane of existence. Used primarily in fantasy and science fiction. His quantum state had become unstable, and he began phasing out of our reality at random.