you still don't get it...

He's asking about Picking Up Stock.

Example:-
Today, you bought Maybank 1000 units in Contra account, when you buy on Contra, you are basically borrowing money from Rakuten to pay for this Maybank 1000 units
It will show up in the Pickup Stock list with the due date on T+2, 2 trading days after the day you made the order.

From the day you bought till T+2, you need to Pickup the stock by having sufficient funds inside your Contra account to offset for the sum that Rakuten paid for you. Once you pickup the stock, by end of day the fund will be transferred to Rakuten then the Maybank shares officially become yours.

If never pick up, Rakuten will force sell on T+3 with their mechanism at market trading price (actual cost I've no idea).

His question now is, if he bought 1000 units on Contra, can he only pickup 500 and let the system sell the balance 500 units? In the interface, it's only selecting the counter and selecting pickup, never allow to enter quantity to pickup. I got no idea how to answer his question.

I'm not sure what will happen if he sold the stock partially before T+2 don't want anyhow advise haha.

Why not sell here buy there if your number of shares not too much? I don't know how much you're talking about though haha

Put single la then number put 1234567