On contracts subject to the minimum requirement, you are not be able to make a buy offer in a designated contract if your offer, when matched, does not enable you to meet the minimum requirement. In other words, if you didn't own any shares in a designated contract with, for example, a 100-share ownership minimum, you wouldn't be able to input an offer to buy fewer than 100 shares. If you already owned 50 shares in this same market, you would be required, when trying to buy more, to make an offer for at least another 50.
Likewise, in this same hypothetical market with a 100-share minimum, you would not be able to enter an offer to sell a quantity of shares if that offer, when fully matched, left you with ownership of fewer than 100 shares. There is no restriction on sell orders that would fully liquidate an open position.