Sir, in layman’s language I will explain you.
From holdings, if it’s from demat or BTST, next day or later anyday, if you sell some shares, you place sell request by authorising through your TPIN of CDSL or NDSL.
now when you sell by putting your desired price, order goes to pending order followed by if price touches, it shows in executed order which will reflect in position by a writeup ‘sold holding’ with negative entry. Example (-200 xyz shares, avg price 131). On same time , if you check your holding, it will show 0 qnty xyz shares.
So the above is a request to sell which broker with the help of demat authority will settle or neutralised by deducting that many shares from your store or holdings which will be executed post operation or day end.
First thing Now you change that into cnc or mis or vice-versa, it won’t make any difference on your p&l. As anything comes in position, first thing in share market, it will be considered as intraday trading.
So if incase someone will click on exit from position, it will show buy window. Or if someone will buy same number share from watchlist, automatically, it will be settled or squared off agaist the sell request number. And position entry will show 0 insted of -, and your sell request for holdings will be cancelled. Your holdings wil again show your shares that you have bought earlier with same avg price. Which means it is safe, untouched.
Please understand,what is shortsell, check YT videos. So to avoid any loss, post the - entry which is sell order, a trader need to buy at lower price then his selling price. So he/she can gain profit. Hope this has cleared your doubt.