To reduce the speed, rate, or intensity of something.
To simplify or reduce one's expectations or commitments, especially in work hours: “28 percent said that they had downshifted and voluntarily cut back on their income in some way … to reflect changes in priorities”(Carey Goldberg).
To shift (a motor vehicle) into a lower gear.
To reduce in speed, rate, or intensity: “The president is downshifting his confrontational rhetoric and reaffirming his readiness to talk arms control”(Newsweek).
To simplify or reduce one's commitments in (one's life).