Are you firmly pressing the brake pedal when trying to move the shifter?
That's supposed to be a mechanical linkage.
On my 2006 Forenza, I had a problem where the shifter did not change the transmission as needed. The Problem turned out to be a Shift-Selector Position switch on the outside of the AT, which, of course, was NOT covered under the Power Train Warranty.
That little switch wound up costing me $145 to replace, at the dealer.
I hope your solution is cheaper than that.