Yes ,you can. Select that position and square it off or from market watch initiate a new sell order with same quantity and underlying.
The only condition is stock should be allowed to trade in intraday as few are not allowed for example which comes under Trade for trade segment in NSE and should be compulsory taken for delivery.
and what would be the brokrage charges applicable in this case, CNC or MIS ? I think CNC charges are more.
this would be treated as an intraday/MIS trade, you can compare the charges in the brokerage calculator on Zerodha website
Buying and Selling on same day will be treated as Intraday trade and will be charged accordingly, you can calculate charges on Brokerage Calculator.