Normally, the print is made to separate easily from the raft by minimizing layer adhesion between the first layer of the actual part and the last layer of the raft.
If this isn't happening with your prints, you likely need to adjust some settings in your slicer. You need to ensure that the first part layer is more than a normal layer height above the top raft layer (in Cura Slicer, I believe this would be the First Layer Thickness); this should be comparable to the Z distance allowance for supports to be removable. You may also want or need to adjust the line width and temperature for the first part layer -- too wide a line may stick too well, and if the first layer is too hot, the same will occur.
It may require several test prints to find just the right settings, though I'd start with resetting your slicer to its default for the printer and materials you're using, and start any adjustments from that base.