If you sell your holdings then as per mandate you will receive 80% of the value of your holdings. The remaining funds will be released into your account on the next trading day. You can use these funds for purchasing other shares, initiate F&O trades as well as for intraday trades.
In case you want to repurchase your holdings back then you will not be able to purchase the whole value of the shares you have sold but only 80% of the value of shares with the money credited.

We recommend you not initiate any intraday trades with the credited margins if you want to repurchase your holdings on the same day, as it may lead to a margin penalty by the exchange as per rules.