In theory, you could change the Earth’s rotation speed using reaction wheels built on the poles. The only problem is that these reaction wheels would have to be comparable in mass to the Earth itself, which opens up some problems. Among the ones I can think of:

• A special motor and axle would have to be made to handle the extreme weight of the wheel.

• Making an object comparable in mass to the Earth is an obviously difficult task.

• They could use less mass and get the same result by spinning the wheels faster. However, if they relied too much on the spinning, the wheel might spin so fast that centrifugal force destroys it.