The question doesn't seem to forbid technological methods, so there are a few options there.
The obvious solution would be to put a giant Catherine wheel of angled thrusters around the Equator, and start making the thing rotate. You may want to build a geostationary ring around the planet and link it with the surface with space elevator cables and put thrusters on the circle, in order to avoid blowing the atmosphere away. Keeping the contraption stable and in one piece will require some work, but I assume that's the kind of small engineering problems that won't stop you. You can also replace the atmosphere afterwards (or store it for the duration).
The problem is, you have to overcome the attraction between the tide bulge and the star, so this will require some serious impulse from your planetary thrusters. Which means big, expensive thrusters and the risk of ripping the entire planet apart and turn it into a molten ball of volcanic madness. So the brute force approach is not a good idea.
Instead of trying to make it rotate in one go, you can impart some pendulum movement, pushing in one direction then the other, making it follow the final phase of tidal locking in reverse. At some point, the pendulum movement will be big enough to make a complete revolution, at which point you can simply keep pushing to accelerate to the required rotation speed.
Now, what engines to use? Low-grade mass drivers would make you either dig giant holes in the surface or require lots of mass from elsewhere in the system. You could if you are in a hurry (those are cheap, low Isp/high impulse engines), but that's rather inelegant.
You could use photonic thrusters (aka giant spotlights) if you have good powerplants like matter-energy converters, are in no hurry and there is no-one flying around to be dazzled. More traffic-friendly exotic versions may be possible, for example emitting neutrinos or gravitational waves, in case your neighbours complain about the light show.
There is a middle ground of particle accelerators, requiring much less mass (and being more refined) than the mass drivers, but giving more thrust than pure photonic engines. The simplest version will heat matter into superhot plasma and let it escape by a nozzle at some fraction of c.
Of course, you have a big fusion powerplant already available, so you can take advantage of that. If you are in no hurry, put giant solar sails on your orbital ring and turn it into a (solar) windmill. Feel free to put mirrors all around the star to help concentrate energy on the sails. Or, if you have fancier tastes, put a light Dyson swarm there and have the collectors beam the power with lasers or focused particle accelerators. That may help avoiding cooking the surface with the unfocused mirrors.
Alternatively, if you don't want to build things on the planet itself, put those on local planetoids and move them around. With the right grazing trajectories, you can use gravitational tugging to start making the planet wobble. Once it starts rotating, a low orbit, fast-orbiting moon may help a bit for accelerating it. Be careful to not overdo it, you may cause more volcanisme than desired otherwise.