Some models use an tamper-resistant screw which can be removed with a specially-designed tool available from home improvement stores & appliance parts stores.
But some folks just use a hammer to tap and loosen the screw, then a "star", t-type, or small flathead screwdriver can be used to remove the screw.
Sometimes the screws are tough, so you may only be able to just bend the post slightly with a punch, then a small flat blade will "grab" enough to turn the screw. Pliers on the handle will help, too.
Another creative solution is to use a hacksaw or a Dremel tool to carefully cut a slot in the head so a flatblade will fit it.
We're happy to help and we appreciate your thoughtful rating of our answer.