That is absolutely possible, provided your broker allows you to do so. Nowadays, most brokers will allow you to take intraday trading positions without putting in any cash. If you have specific shares in your demat account (list of stocks can be availed from your broker on which margin is available), then you can use that as margin. Of course, there will be the haircut. For example, if you have shares of Rs.1 lakh then the broker will allow you to use up to Rs.50,000 of margin for intraday trading. Remember, you can still leverage this Rs.50,000 to the extent of 5-6 times depending on your agreement with the broker. There are a few things to remember.
Any loss on your intraday trades has to be made up in cash by you on the same day. Otherwise, the broker will have to sell your shares to put in the margin. Secondly, if there is a system problem or if you forget to close the trade, then the shares will come into your demat account. For that you either have to pay the margin by T+1 day for delivery or the shares will be sold. This is a good way to trade when you are trading with complete discipline and not being lax with your stop losses and your profits targets.