I think you have to open a demat account or map an existing demat account cos they insist on mapping a demat account if you want to trade in equity segment - intraday or delivery.
You have to give them an intimation in writing that you want to trade in Equity segment and they should enable.
If you are trading with Zerodha I found this on their website: https://zerodha.com/download/Change%20Of%20Information%20Documents/Addition%20Segments.doc maybe you can use.
Call zerodha +91 80 4040 2020.
They will explain you.
You need to submit additional forms
most probably i will be doing day trading that too with the leverage available.
In that case do i need a demat account ?
Anyways Thanks for the reply 
Yes, demat has become mandatory as stiplulated by the exchange for all Equity Trading.
This is because of circumstances, in which your stocks may be pushed to demat account, if you dont find a buyer to sell it back during the trading hours.
Thats clears it. Thanks Guruji