how can I move coin from stake to spendable? if I set reserve, it is still in stake
It would help to know exactly which coin you are referring too.
But in General terms,
All coins are spendable except when that block that contains the coins stake,
when it does stake , those coins can not be used until the staking process is finished, for some coins that could be as few as 10 new blocks found, others may be 120 blocks varies with which coin you are using.
Here is a link on how to use Coin Control, it was made for
ZEIT , but should be basically the same for any other PoS coin.
https://bitcointalksearch.org/topic/m.10296134Using coin control you can select the exact block, so you can always select one that is not about to stake.
If you don't use coin control, the coins are selected at random.
FYI:
If you encrypt your wallet , no coins will stake until you unlock the wallet for staking.