If the crown has Allen head bolts on the rear then it should indicate the steerer can be removed.
There should be a Circlip at the bottom of the steerer to stop it beings pulled up through the crown so you need to push it down to get it out.
The crown may have a shim to allow the use of other steerer diameters but that shouldn't really impact the removal. You should also have a crown race shim on the top of the crown that slips over the steerer thats to hold the headset race in place. If the headset race is still on (and sometimes when it isnt), these often adhere to the steerer which might explain why the steerer turns but doesn't come out (with the Circlip at the bottom and the crown race shim on top, it's all holding the steerer in place).
Solution: bit of force, tapping the steerer from the top should do it. Don't use a metal hammer as you could damage the steerer making it hard to refit/get through the crown. Block of wood first or a rubber mallet and you should be OK.