Its as easy as changing any other hitch, takes about 15mins. Just the 2 horizontal bolts to undo but ensure rear bolt goes back through front of hitch damper when you replace it.
The post by Jack+Jon is right but to add on that you really need a steel dowel that goes through the rear bolt hole (one furtherst from the hitch coupling) the same size as the bolt to retain the damper whilst you interchange the two hitches. The draw bar slides inside the main housing which is inside the hitch so the dowel is shorter in order to be able to remove the hitch so what you have to do is tap the bolt partly out then enter the dowel followed by tapping the dowel which the bolt drops out leaving the dowel in place. Re-fitting is opposite whereby you tap the dowel with the bolt so the dowel falls out leaving the bolt in place complete with damper in place. Apply the two nuts and tighten to the correct torque and that's it, job done!
Alko AKS3004 instruction manual might be of interest.
Click here to view and save a copy.
If buying a new stabiliser hitch, dowel referred to above for damper, will be included.