To carry out an action, the result of which is a significant change, or an altered circumstance.
To be of importance; to matter.
To change drastically in a fundamental way, often for the better; to change to the opposite (opinion or position).
To consider from a different viewpoint.
(often with a unit of time) To produce; to output; to generate.
To suddenly change or reverse one's opinion, point of view, stated position, behaviour, etc.
To reverse an expected outcome (of a game, etc.), usually from a losing outcome to a winning one; to return (a business, department, etc.) to effectiveness, profitability, etc.
To physically rotate (usually around a vertical axis) for a half turn (180 degrees), a whole turn (360 degrees), or an indefinite amount.
To convert (an agent) to work for one's own side.