Well the staking with stake lock isn’t supposed to be a thing you can change your mind back and forth on. That’s why the stake lock exists (presumably), to help us fight our urges to liquidate. It is a pain but I can see why it is that way.
Having said that, once you choose your duration in stake lock it is meant to be a reliable number so you have to put at least the same amount of days you have left on your staking term. And ride out the remainder without the lock on. It sucks but the incentives are well worth keeping it locked away for me.